Medicare Provider Enrollment: The Complete PECOS Credentialing Guide for 2026

Traditional Medicare does not credential providers the way a commercial plan does. There is no contract negotiation and no committee vote. There is an enrollment application, a Medicare Administrative Contractor (MAC) that screens it, and a set of federal regulations that decide when you can bill, how far back you can bill, what you must report and what happens when you do not. Get the mechanics right and Medicare is one of the more predictable payers to onboard. Get them wrong and you are looking at unpaid dates of service that can never be recovered.

This guide covers the whole cycle for physicians, non-physician practitioners (NPPs), group practices and the institutional providers that share the same system: NPI prerequisites, the CMS-855 family, PECOS and the Identity & Access system, MAC jurisdictions, fees, screening, effective dates, the denials that show up after approval, and the maintenance that keeps an enrollment alive. Every form number, deadline and dollar figure was checked against a CMS or federal regulatory page on 2026-09-13; sources are listed at the end. MACs interpret and rules change, so confirm anything unusual with your MAC before filing.

Before you file: NPI type and NPPES accuracy

CMS lists obtaining a National Provider Identifier as step one of Medicare enrollment, ahead of the PECOS application itself (Become a Medicare Provider or Supplier). The NPI is a 10-digit, intelligence-free identifier that stays with a provider regardless of name, address or specialty changes (NPIs | CMS).

There are two entity types, and the distinction runs through every Medicare transaction that follows:

• A Type 1 NPI is assigned to an individual. Every physician, NP, PA, therapist or other rendering practitioner needs one, whether solo, employed or contracted (NPI Fact Sheet).
• A Type 2 NPI is assigned to an organization: a group practice, clinic, hospital, ASC, lab or other entity that bills under its own tax identification number (NPI Fact Sheet).

A sole proprietor billing under a Social Security number enrolls with a Type 1 NPI only. A single-physician professional corporation billing under an EIN generally needs both. The IRS document that will go in the application settles it: the name and TIN on that letter determine which NPI the billing entity needs.

Before touching PECOS, open the NPPES record for every NPI you will use and reconcile it against the IRS letter, the state license and the location you are about to enroll. Covered providers must update NPPES within 30 days of a change (Unique Identifiers FAQs | CMS). A legal business name that differs by a comma, an abbreviation or a missing "LLC" between NPPES, the CP 575 and the CMS-588 is one of the development reasons CMS itself calls out (Avoiding Processing Delays). Fix NPPES first; the MAC will compare.

NPPES pre-flight checklist:

• Type 1 NPI for each rendering practitioner, legal name matching the state license
• Type 2 NPI for the billing organization, legal business name matching the IRS document exactly
• Primary practice location matching the address you will enroll in PECOS
• Taxonomy code matching the specialty you will enroll under
• Contact details current, and the NPPES login tied to an I&A account you can actually access

Which CMS-855 application applies to you

The CMS-855 family is the paper expression of the data PECOS collects online. Even if you never print a form, you must know which scenario you are in, because PECOS asks at the start and the MAC screens against it.

Three scenario rules cover most practices:

1. A physician joining an existing group files an 855I with a reassignment to the group in Section 4F. The practitioner signs Section 15B and the group's authorized or delegated official signs 15C (Consolidated CMS-855I/CMS-855R Enrollment Applications). In PECOS this happens in the Reassignment topic.
2. A new group needs an 855B for the entity first, or concurrently, because there is nothing to reassign to until the group has a record.
3. A practitioner who never bills but signs orders for DME, labs, imaging or home health needs an 855O, an approved 855I enrollment, or an opt-out on file, or the supplier's claims deny (Ordering & Certifying | CMS).

The 855R merger in practice

Adding, changing or terminating a reassignment is now an 855I change-of-information transaction: check "reporting a change" in Section 1A, select "Reassignment of Benefit Information" in 1B, complete Sections 1, 2A, 3, 4F, 12, 13 (optional) and 15, and mark Add or Terminate with an effective date in 4F (Consolidated CMS-855I/CMS-855R Enrollment Applications). Groups accepting or ending a reassignment file the same 855I. CMS said the 855B would carry reassignment data in a future revision; verify the current 855B version with your MAC before filing on paper.

PECOS, the I&A system and surrogates

CMS describes PECOS as the online Medicare enrollment system and states that PECOS applications are processed more quickly than paper (Manage Your Enrollment | CMS). CMS's own delay analysis found development requests exceed 50 percent for paper applications and run about 25 percent for web applications (Avoiding Processing Delays). Paper is still allowed for anyone who cannot use PECOS, but a practice with internet access has no good reason to choose it.

Getting a login

You log into the Identity & Access (I&A) Management System, which issues one credential for NPPES, PECOS, PEPPER and CBR. Multi-factor authentication has been mandatory since April 21, 2022, and passwords expire every 60 days; an expired password blocks login but does not affect the NPI, the enrollment or claims (Identity & Access Frequently Asked Questions).

All role descriptions are drawn from the Identity & Access Frequently Asked Questions.

Surrogacy mechanics

A connection lets one organization act for a provider in PECOS, NPPES or the reporting systems. Either side can initiate: the surrogate uses Find Provider under My Connections and requests specific business functions, or the provider uses Add Surrogate; the other party approves. Approved connections do not expire, either party can disable one at any time, and PECOS access can take up to three hours to appear after approval (Identity & Access Frequently Asked Questions).

Two details trip up practices that outsource enrollment. First, a group's connection to a surrogate exposes only the group's own record, not the records of practitioners who reassigned to it; each individual approves the surrogate separately, or the surrogate uses the Optional Surrogacy Confirmation paper process for an individual who cannot log in (Identity & Access Frequently Asked Questions). Second, a surrogate has no effect on processing timeframes, and the signer remains legally responsible for the application; CMS's 2026 update repeats that providers are responsible "regardless of whether another party completed the application" (Medicare Provider Enrollment Compliance Conference March 18, 2026). A third-party company registers in I&A through its own Authorized Official before it can connect to any client. If you would like an approved surrogate to run this process, see our credentialing services.

Finding the right MAC for your state

Applications go to the A/B MAC for the state where the practice location sits, not where the corporate office or the biller is. CMS divides the country into 12 A/B MAC jurisdictions, each with its own enrollment unit, portal and queue (Who are the MACs | CMS). Submitting to the wrong contractor is on CMS's list of delay causes (Avoiding Processing Delays).

Sources: the individual "Who are the MACs: A/B MAC Jurisdiction" pages listed at the end. Home health and hospice claims follow a separate HH+H map, and DMEPOS suppliers enroll through the National Supplier Clearinghouse. MAC contracts are re-competed periodically (JF was re-awarded to the incumbent in August 2025), so confirm the current contractor on the CMS page before you file. A practice with locations in two jurisdictions enrolls with each MAC, and opt-out affidavits must likewise be filed with every MAC where the practitioner sees Medicare patients.

Step by step: filing the enrollment

Written for a physician or NPP joining or forming a group; institutional providers follow the same skeleton with the 855A, a state survey and a longer timeline.

1. Confirm the NPI and clean up NPPES. Do not start PECOS until the legal name, address and taxonomy are right.
2. Establish I&A access. The practitioner registers as an Individual Provider; the group's AO registers and adds the organization as employer, then adds AMs and SEUs and approves surrogate connections. Budget a week if the AO has never registered.
3. Gather supporting documents (list below).
4. Pick the scenario in PECOS: new enrollment, reassignment to an existing group, new group plus reassignments, change of information, or revalidation. The wrong scenario is a common reason an application is returned.
5. Complete the topics. PECOS pre-fills from NPPES and asks only for what the scenario needs (Manage Your Enrollment | CMS). Watch practice location, correspondence and special payments addresses, the reassignment topic, adverse legal history and the contact person.
6. Complete the CMS-588 EFT topic and upload a voided check or bank letter showing the legal business name, routing and account number. The 588 must be signed by the same enrolling individual or authorized official who signs the 855, and EFT is mandatory for anyone enrolling or updating enrollment data (Avoiding Processing Delays; CMS-588).
7. Decide PAR or non-PAR. Filing the CMS-460 with the initial enrollment makes participating status effective with the enrollment; otherwise the annual open enrollment window applies.
8. Pay the application fee if your enrollee type owes one. Physicians, NPPs and physician groups do not.
9. E-sign. Every required signer signs inside PECOS or on an uploaded certification statement; surrogates cannot. Missing or wrong signatures are a leading delay after missing documents (Avoiding Processing Delays).
10. Record the application ID and submission date. That date is potentially your effective date of billing privileges.
11. Watch for development. If the MAC needs anything, you have 30 days to respond completely; if the period lapses the MAC rejects the application, and a second request is at its discretion (Avoiding Processing Delays).
12. Start EDI enrollment in parallel so you can submit electronic claims the day the PTAN issues.
13. On approval, reconcile the letter: PTAN, effective date, locations, reassignments and specialty. Errors here become denials later.
14. Load the PTAN, effective date and retroactive window into the practice management system and release held claims.

Supporting documents to have ready

• IRS document confirming the legal business name and TIN (CP 575 or equivalent)
• State license for each practitioner, plus DEA where relevant to the specialty
• Board certification if the enrolling specialty requires it
• Voided check or bank letter on letterhead for the CMS-588
• Documentation and final resolution of any adverse legal action
• Business license or certificate of good standing where the state issues one
• For NPPs, collaborative or supervisory agreements if the state requires them
• Organizational chart and ownership disclosure for multi-owner entities; CMS clarified in 2026 that the MAC may request any documentation needed to verify ownership or management (Medicare Provider Enrollment Compliance Conference March 18, 2026)

The application fee

CMS set the calendar year 2026 application fee at $750 (MLN9658742 Medicare Provider Enrollment). It applies to institutional providers and to suppliers such as DMEPOS suppliers and opioid treatment programs when they enroll, re-enroll, revalidate or add a practice location. Physicians, NPPs, physician organizations, non-physician organizations and MDPP suppliers do not pay it (MLN9658742 Medicare Provider Enrollment). The fee is paid through PECOS, a hardship exception can be requested in writing, and the amount is adjusted each calendar year, so check the current figure if you are reading this after December. Filing without a required fee triggers development and resets your clock.

Risk screening levels and fingerprinting

Every initial application, revalidation, change of ownership and new location is screened at a categorical risk level (42 CFR 424.518, Screening levels for Medicare providers and suppliers):

Any enrollee moves to high risk after a payment suspension in the last 10 years, an OIG exclusion, a revocation in the prior 10 years, a Medicaid termination or a qualifying final adverse action (42 CFR 424.518). For a typical physician practice the practical effect is limited screening, which is why physician applications move faster than facility applications.

Site visits

The MAC or a National Site Visit Contractor can visit any Part A or B provider or supplier unannounced, not only those in the moderate and high categories; inspectors carry photo identification and a signed CMS authorization letter (MLN9658742 Medicare Provider Enrollment). A location that is closed during posted hours, unsigned or a mail drop is grounds for denial or revocation. Enroll only locations where a stranger can walk in and find the practice operating.

EFT (CMS-588) and EDI enrollment are two different things

The CMS-588 tells the MAC where to deposit money. EDI enrollment tells the MAC who may send your electronic claims and receive your remittances. Both are required to bill and neither is automatic. Each provider that intends to submit electronic claims must execute the CMS standard EDI enrollment form and submit it to the local MAC, which issues a submitter ID that serves as the provider's electronic signature; a clearinghouse or billing service holds its own submitter ID with each MAC and you authorize it to send on your behalf, and an organization with multiple PTANs can file one EDI enrollment covering all components (How to Enroll in Medicare Electronic Data Interchange | CMS). Start EDI enrollment when the 855 is submitted, not when it is approved; it is a separate queue and waiting for the PTAN letter adds weeks of held claims.

Master checklist

• NPPES reconciled; Type 1 and Type 2 NPIs correct
• I&A roles set; surrogate approved by both the group and each individual
• Correct PECOS scenario; locations entered exactly as they exist
• Adverse legal history disclosed with resolution documents
• CMS-588 with voided check or bank letter, signed by the 855 signer
• CMS-460 decision made; fee confirmed not owed or paid
• All e-signatures by the practitioner and the group's AO or DO
• Submission date and application ID recorded
• EDI enrollment submitted to the same MAC with clearinghouse authorization
• Development answered within 30 days
• Approval letter reconciled and loaded into the billing system
• Revalidation date logged; Medicare Advantage applications started

Effective dates, retrospective billing and the realistic timeline

This section decides whether your first six weeks of visits get paid.

The effective-date rule

For physicians, NPPs, physician and NPP organizations and a list of other Part B supplier types, the effective date of billing privileges is the later of the date the MAC received an application it subsequently approved, or the date the provider first furnished services at the new location (42 CFR 424.520, Effective date of Medicare billing privileges). The approval date is irrelevant; the filing date is what counts, which is why a clean application filed on day one is worth more than a perfect one filed on day thirty. Reassignments follow the same rule (Medicare Provider Enrollment Compliance Conference March 18, 2026, citing 42 CFR 424.522(a)), and an 855O enrollment is effective on the date the MAC received it if all other requirements are met (same source, citing 42 CFR 424.522(b)).

Retrospective billing

Those same provider types may bill for services furnished at the enrolled location up to 30 days before the effective date if circumstances precluded enrolling in advance, or up to 90 days before it if a Presidentially declared Stafford Act disaster precluded enrollment, provided all requirements including state licensure were met on the dates of service (42 CFR 424.521, Request for payment by certain provider and supplier types). A physician who started seeing Medicare patients on March 1 and whose application was received April 1 can, once approved, bill back to March 2; earlier visits are unrecoverable. The 90-day window exists only for declared disasters and should never be planned around. The 30-day window does not apply to 855A institutional providers, whose dates tie to survey and certification.

Timeline

Neither CMS nor the regulations promise a processing time. CMS does say PECOS applications process faster than paper (Manage Your Enrollment | CMS), that 30 to 35 percent of applications are delayed with an incomplete application typically delayed 30 to 45 days, and that a development request carries a 30-day deadline (Avoiding Processing Delays). MACs publish their own processing goals; check yours and treat every figure below as a range, not a commitment.

Plan start dates around these ranges. If a physician must see Medicare patients before approval, file before the first date of service so the effective date, not the retrospective window, protects the revenue.

What goes wrong after enrollment: the denials and how to fix them

Approval is where the second set of problems begins. These are the enrollment-driven denials practice managers see most.

Two points bear stressing. The effective-date rule and retrospective window are regulatory; the MAC cannot grant an exception because your credentialing was slow, and appeals on that ground fail. And most of these denials are visible in PECOS before the first claim goes out: pull the enrollment record after every approval and every change and compare it line by line with what the billing system transmits.

Maintaining the enrollment: reporting, revalidation, deactivation and opt-out

An approved enrollment carries ongoing obligations, and the penalties run from held payments to a multi-year bar.

The 30-day and 90-day reporting rules

Physicians, NPPs and their organizations must report within 30 days a change of ownership, any adverse legal action, and any change, addition or deletion of a practice location; every other change is due within 90 days (42 CFR 424.516(d), Additional provider and supplier requirements). Other provider types follow the same 30-day rule for ownership or control, including changes in authorized or delegated officials, and locations, with 90 days for everything else (42 CFR 424.516(e); Medicare Provider Enrollment Compliance Conference March 18, 2026). Documentation supporting claims and orders must be kept for 7 years from the date of service (42 CFR 424.516(f)).

Late reporting is not a foot fault. Failure to report is a stand-alone revocation reason, and CMS confirmed in 2026 that a revocation for failing to timely report ownership, adverse legal action or location changes can be made effective retroactively to the day after the report was due (Medicare Provider Enrollment Compliance Conference March 18, 2026, citing 42 CFR 424.535(g)). Every claim paid after that date becomes an overpayment. Changes people forget belong in the 90-day bucket: a new managing employee, a new billing agency, a changed correspondence or payment address, a new bank account (with a CMS-588), a name change, and adding or removing a reassignment.

Revalidation every 5 years (3 for DMEPOS)

Most providers and suppliers revalidate every 5 years, DMEPOS suppliers every 3, and CMS can request an off-cycle revalidation at any time (Revalidations (Renewing Your Enrollment) | CMS). Due dates appear on the Medicare Revalidation List about 7 months ahead, and the MAC sends a notice by email or mail roughly 3 to 4 months before the date (Revalidations (Renewing Your Enrollment) | CMS; MLN9658742 says 90 to 120 days). A "TBD" entry means you are not yet due; an unsolicited revalidation will not be processed as one.

There are no extensions or exemptions. Miss the date and the MAC can hold payment and deactivate; once deactivated you must submit a complete new application rather than a revalidation, and Medicare will not pay for services furnished during the deactivated period (Revalidations (Renewing Your Enrollment) | CMS). Do not wait for the letter, which goes to whatever address is on file; check the list for every NPI you manage each quarter.

Deactivation versus revocation, and reactivation

Deactivation is administrative. CMS may deactivate when a provider submits no Medicare claims for 6 consecutive calendar months, fails to report a change on time, fails to furnish requested information within 90 days, is not operational at the enrolled location, dies, voluntarily withdraws, or in certain HHA ownership transactions (42 CFR 424.540, Deactivation of Medicare billing privileges). To reactivate, the provider recertifies that the enrollment on file is correct and supplies anything missing, though CMS may require a complete new CMS-855; no payment is made for services furnished while deactivated, and reactivation is effective on the date the MAC received the submission it approved (42 CFR 424.540). There is no reenrollment bar.

Revocation is punitive. CMS may revoke for more than 20 listed reasons, including noncompliance with enrollment requirements, exclusion or debarment, qualifying felonies within 10 years, false or misleading application information, not being operational, abuse of billing privileges and failure to report (42 CFR 424.535, Revocation of enrollment in the Medicare program). A revocation carries a reenrollment bar of 1 to 10 years, up to 20 years for a second revocation, plus up to 3 years for attempts to circumvent it (42 CFR 424.535(c)). Revocation is generally effective 30 days after the notice is mailed, but abusive billing, false application information, DEA surrender under a show-cause order and state prescribing-authority actions carry retroactive effective dates (42 CFR 424.535(g); Medicare Provider Enrollment Compliance Conference March 18, 2026). A revocation notice has appeal and corrective action plan deadlines measured in days; involve counsel the day it arrives.

An 855O-only practitioner who has not appeared as the ordering, certifying or referring provider on any Part A or B claim for 12 consecutive months can have that enrollment deactivated (42 CFR 424.547, summarized in the Medicare Provider Enrollment Compliance Conference March 18, 2026). Check hospital-employed order-only physicians against this annually.

Voluntary withdrawal and opt-out

A practitioner leaving Medicare entirely should file a voluntary withdrawal within 90 days (30 for DMEPOS suppliers) so claims cannot be submitted under the record after departure (Manage Your Enrollment | CMS). A practitioner leaving a group but staying in Medicare needs a reassignment termination, not a withdrawal.

Opting out is the opposite of enrolling. An eligible physician or practitioner files an affidavit with the MAC and signs a written private contract with each Medicare patient under which nobody bills Medicare and the patient pays out of pocket. Opt-out periods last two years and renew automatically unless cancelled, and an opt-out can be terminated early within 90 days of the initial affidavit (Manage Your Enrollment | CMS). Affidavits go to each MAC where the practitioner practices. An opted-out practitioner can still order, certify and refer and appears on the Ordering and Certifying file (Ordering & Certifying | CMS), but cannot reassign to a group for Medicare purposes, which is the point most groups hiring a concierge-style physician miss.

Maintenance calendar

Medicare Advantage is credentialed separately

Enrolling in traditional Medicare does not put you in network with any Medicare Advantage plan. Each MA organization must have written provider selection policies, must credential physicians and other professionals itself with a written application, primary-source verification of licensure, disciplinary history, eligibility for Medicare payment and site visits, and must recredential at least every 3 years; it may not contract with excluded providers and must follow the rules on opted-out physicians (42 CFR 422.204, Provider selection and credentialing).

In practice a new physician needs the PECOS enrollment plus a separate credentialing application, usually through CAQH, with every MA carrier the practice participates with, followed by a contract or roster load with each. The PECOS approval is a prerequisite MA plans check, not a substitute. MA timelines are often longer than the MAC's, and an MA effective date will not automatically match the Medicare one. Fast Track Credentialing handles the Medicare enrollment and the MA plan credentialing as one project so the dates line up; pricing and ordering are here.

Frequently asked questions

Can a physician see Medicare patients before the PECOS application is approved?

Yes, but only dates of service on or after the effective date, plus the 30-day retrospective window, will be paid. Because the effective date is the later of the filing date or the first date of service, file before the first Medicare visit (42 CFR 424.520; 42 CFR 424.521). Services more than 30 days before the filing date are not billable.

Does a physician have to pay the Medicare application fee?

No. Physicians, NPPs, physician organizations, non-physician organizations and MDPP suppliers are exempt. Institutional providers, DMEPOS suppliers and opioid treatment programs pay the calendar-year fee, which CMS set at $750 for 2026 (MLN9658742 Medicare Provider Enrollment).

Is the CMS-855R still used?

No. CMS merged it into the 855I; MACs began accepting the revised 855I on September 1, 2023, and reassignments are now handled through Section 4F or the Reassignment topic in PECOS (Consolidated CMS-855I/CMS-855R Enrollment Applications). If a form or instruction still refers to an 855R, verify with your MAC before filing.

Can our credentialing company sign the application in PECOS for the doctor?

No. Surrogates can prepare, upload and submit, but CMS states that surrogates may not sign, electronically or otherwise, any application on behalf of another individual (Identity & Access Frequently Asked Questions). The practitioner signs their own record and the group's authorized or delegated official signs for the group.

How do I know when our revalidation is due?

Search the Medicare Revalidation List for each NPI. CMS posts due dates about 7 months ahead and the MAC sends a notice roughly 3 to 4 months before. A "TBD" entry means no date has been set and you should not submit yet (Revalidations (Renewing Your Enrollment) | CMS).

What is the difference between deactivation and revocation?

Deactivation stops billing privileges for administrative reasons, such as 6 months without claims or a missed revalidation, and is cured by reactivation with no reenrollment bar, though the deactivated period is unpaid (42 CFR 424.540). Revocation is a sanction that terminates the enrollment and carries a bar of 1 to 10 years, up to 20 for a second revocation (42 CFR 424.535).

We moved offices two months ago and did not report it. What should we do?

Report it in PECOS today. Location changes are due within 30 days (42 CFR 424.516(d)), and an unreported move can lead to a failed site visit, deactivation, or a revocation with a retroactive effective date (Medicare Provider Enrollment Compliance Conference March 18, 2026). Filing late is far better than being found out.

Does Medicare enrollment mean we are in network with Medicare Advantage plans?

No. Each MA organization credentials and contracts on its own under 42 CFR 422.204, with primary-source verification and recredentialing at least every 3 years. Treat each MA plan as a separate credentialing project that requires the PECOS enrollment as a prerequisite.

Can an opted-out physician work at our group and have us bill Medicare for their services?

No. While opted out, neither the physician nor anyone else may bill Medicare for that physician's covered services; the patient pays under a private contract (Manage Your Enrollment | CMS). The physician can still order and refer. Terminating an opt-out is only possible within 90 days of the initial affidavit or at the end of a two-year period with at least 30 days' notice.

How long does Medicare enrollment take?

There is no guaranteed timeframe. CMS says PECOS applications are processed more quickly than paper and that incomplete applications are typically delayed 30 to 45 days (Manage Your Enrollment | CMS; Avoiding Processing Delays). In practice a clean PECOS application for a limited-risk physician or group tends to resolve in roughly 30 to 60 days, paper and developed applications take longer, and facility or high-risk enrollments can run several months. Check your MAC's published figures before promising a start date.

Medicare enrollment rewards preparation more than any other payer: the effective-date rule means a complete application filed early is worth real money, and the reporting and revalidation rules mean the work does not end at approval. If your practice would rather hand the PECOS, I&A, MAC and Medicare Advantage work to a team that does it every day, contact us with the practitioner's NPI and start date and we will map the timeline. Fast Track Credentialing is an independent credentialing service and is not affiliated with or endorsed by Medicare, CMS or any Medicare Administrative Contractor.

Sources and verification

All pages below were opened and read on 2026-09-13. Checked 2026-09-13.

• Become a Medicare Provider or Supplier — https://www.cms.gov/medicare/enrollment-renewal/providers-suppliers
• Manage Your Enrollment | CMS — https://www.cms.gov/medicare/enrollment-renewal/providers-suppliers/chain-ownership-system-pecos/manage-your-enrollment
• Medicare Enrollment for Providers & Suppliers (PECOS landing page) — https://www.cms.gov/medicare/enrollment-renewal/providers-suppliers/chain-ownership-system-pecos
• Enrollment Applications | CMS — https://www.cms.gov/medicare/enrollment-renewal/providers-suppliers/chain-ownership-system-pecos/enrollment-applications
• Revalidations (Renewing Your Enrollment) | CMS — https://www.cms.gov/medicare/enrollment-renewal/providers-suppliers/revalidations
• Ordering & Certifying | CMS — https://www.cms.gov/medicare/enrollment-renewal/providers-suppliers/chain-ownership-system-pecos/ordering-certifying
• MLN9658742 Medicare Provider Enrollment (MLN booklet) — https://www.cms.gov/Outreach-and-Education/Medicare-Learning-Network-MLN/MLNProducts/EnrollmentResources/provider-resources/provider-enrolment/Med-Prov-Enroll-MLN9658742.html
• CMS Forms List | CMS — https://www.cms.gov/medicare/cms-forms/cms-forms/cms-forms-list
• CMS-588 Electronic Funds Transfer (EFT) Authorization Agreement — https://www.cms.gov/medicare/cms-forms/cms-forms/downloads/cms588.pdf
• Consolidated CMS-855I/CMS-855R Enrollment Applications (CMS bulletin) — https://www.cms.gov/files/document/consolidated-cms-8551-bulletin.pdf
• Avoiding Processing Delays (CMS Provider Enrollment presentation) — https://www.cms.gov/Medicare/Provider-Enrollment-and-Certification/MedicareProviderSupEnroll/Downloads/Avoid_Processing_Delays.pdf
• Medicare Provider Enrollment Compliance Conference, March 18, 2026: New Regs for 2026 (CMS presentation) — https://www.cms.gov/files/document/2026-new-provider-enrollment-regulations.pdf
• How to Enroll in Medicare Electronic Data Interchange | CMS — https://www.cms.gov/medicare/coding-billing/electronic-billing/how-to-enroll-medicare-electronic-data-interchange
• Who are the MACs | CMS — https://www.cms.gov/medicare/coding-billing/medicare-administrative-contractors-macs/who-are-macs
• Who are the MACs: A/B MAC Jurisdiction 5 (J5) — https://www.cms.gov/medicare/medicare-contracting/medicare-administrative-contractors/who-are-the-macs-a-b-mac-jurisdiction-5-j5
• Who are the MACs: A/B MAC Jurisdiction 6 (J6) — https://www.cms.gov/medicare/medicare-contracting/medicare-administrative-contractors/who-are-the-macs-a-b-mac-jurisdiction-6-j6
• Who are the MACs: A/B MAC Jurisdiction 8 (J8) — https://www.cms.gov/Medicare/Medicare-Contracting/Medicare-Administrative-Contractors/Who-are-the-MACs-A-B-MAC-Jurisdiction-8-J8
• Who are the MACs: A/B MAC Jurisdiction 15 (J15) — https://www.cms.gov/medicare/medicare-contracting/medicare-administrative-contractors/who-are-the-macs-a-b-mac-jurisdiction-15-j15
• Who are the MACs: A/B MAC Jurisdiction E (JE) — https://www.cms.gov/medicare/medicare-contracting/medicare-administrative-contractors/who-are-the-macs-a-b-mac-jurisdiction-e-je
• Who are the MACs: A/B MAC Jurisdiction F (JF) — https://www.cms.gov/medicare/medicare-contracting/medicare-administrative-contractors/who-are-the-macs-a-b-mac-jurisdiction-f-jf
• Who are the MACs: A/B MAC Jurisdiction H (JH) — https://www.cms.gov/medicare/medicare-contracting/medicare-administrative-contractors/who-are-the-macs-a-b-mac-jurisdiction-h-jh
• Who are the MACs: A/B MAC Jurisdiction J (JJ) — https://www.cms.gov/medicare/medicare-contracting/medicare-administrative-contractors/who-are-the-macs-a-b-mac-jurisdiction-j-jj
• Who are the MACs: A/B MAC Jurisdiction K (JK) — https://www.cms.gov/medicare/medicare-contracting/medicare-administrative-contractors/who-are-the-macs-a-b-mac-jurisdiction-k-jk
• Who are the MACs: A/B MAC Jurisdiction L (JL) — https://www.cms.gov/medicare/medicare-contracting/medicare-administrative-contractors/who-are-the-macs-a-b-mac-jurisdiction-l-jl
• Who are the MACs: A/B MAC Jurisdiction M (JM) — https://www.cms.gov/medicare/medicare-contracting/medicare-administrative-contractors/who-are-the-macs-a-b-mac-jurisdiction-m-jm
• Who are the MACs: A/B MAC Jurisdiction N (JN) — https://www.cms.gov/medicare/medicare-contracting/medicare-administrative-contractors/who-are-the-macs-a-b-mac-jurisdiction-n-jn
• NPIs | CMS — https://www.cms.gov/priorities/key-initiatives/burden-reduction/administrative-simplification/unique-identifiers/npis
• NPI Fact Sheet (CMS, December 2024) — https://www.cms.gov/files/document/npi-fact-sheet.pdf
• Unique Identifiers FAQs | CMS — https://www.cms.gov/priorities/key-initiatives/burden-reduction/administrative-simplification/unique-identifiers/faqs
• Identity & Access Frequently Asked Questions (FAQs), 1/20/2026 — https://nppes.cms.hhs.gov/IAWebContent/FAQs.pdf
• 42 CFR 424.516 Additional provider and supplier requirements for enrolling and maintaining active enrollment status in the Medicare program — https://www.govinfo.gov/content/pkg/CFR-2024-title42-vol3/xml/CFR-2024-title42-vol3-sec424-516.xml
• 42 CFR 424.518 Screening levels for Medicare providers and suppliers — https://www.govinfo.gov/content/pkg/CFR-2024-title42-vol3/xml/CFR-2024-title42-vol3-sec424-518.xml
• 42 CFR 424.520 Effective date of Medicare billing privileges — https://www.govinfo.gov/content/pkg/CFR-2024-title42-vol3/xml/CFR-2024-title42-vol3-sec424-520.xml
• 42 CFR 424.521 Request for payment by certain provider and supplier types — https://www.govinfo.gov/content/pkg/CFR-2024-title42-vol3/xml/CFR-2024-title42-vol3-sec424-521.xml
• 42 CFR 424.535 Revocation of enrollment in the Medicare program — https://www.govinfo.gov/content/pkg/CFR-2024-title42-vol3/xml/CFR-2024-title42-vol3-sec424-535.xml
• 42 CFR 424.540 Deactivation of Medicare billing privileges — https://www.govinfo.gov/content/pkg/CFR-2024-title42-vol3/xml/CFR-2024-title42-vol3-sec424-540.xml
• 42 CFR 422.204 Provider selection and credentialing — https://www.govinfo.gov/content/pkg/CFR-2024-title42-vol3/xml/CFR-2024-title42-vol3-sec422-204.xml