The short answer: What is NPPES? It is the CMS system that assigns your National Provider Identifier (NPI) and stores it. What is PECOS? It is the CMS system where you manage your Medicare enrollment. You need an NPI to enroll in Medicare, but getting one does not enroll you. And CMS says changing your NPPES record does not automatically change your Medicare enrollment record.
What NPPES does
The National Plan and Provider Enumeration System (NPPES) is maintained by CMS. It assigns NPIs to health care providers and is the database that stores and manages them. Under federal rules, the national provider system gives each provider a single, unique NPI and keeps information about every provider it has assigned one to.
CMS describes the NPI as the 10-digit standard unique identifier for health care providers. The NPI standard was adopted under HIPAA.
NPI types: Type 1 is for individual providers, who can hold only one NPI, and Type 2 is for organizations such as hospitals and physician groups, which can hold more than one.
You can apply for an NPI online at the NPPES website, on a paper form, or by authorizing an employer or other trusted organization to get one for you through bulk enumeration.
The NPI is not only a Medicare number. Health plans, including Medicare and private health plans, require NPIs in their administrative and financial transactions.
What PECOS does
PECOS is CMS's online Medicare enrollment management system. CMS lists what you can do in it: enroll as a Medicare provider or supplier, review and update your information, report changes to your enrollment record, withdraw from Medicare, and sign and submit your information electronically. You can also upload supporting documents there, and because PECOS is paperless, nothing needs to go by mail.
PECOS is also where you revalidate (renew) your Medicare enrollment. For help with that, see our recredentialing and revalidation service.
Your Medicare contractor processes enrollment applications and can answer questions about your application. CMS's PECOS page links to a list for finding your contractor.
How the two connect
The order matters. A provider or supplier that is eligible for an NPI must report it on its Medicare enrollment application. Your enrollment information goes on that application. The supporting documentation can include proof of your legal business name, practice location and NPI, if one has been issued.
So you need an NPI before you enroll in Medicare. Still, CMS is clear that getting an NPI does not replace the Medicare enrollment process.
PECOS and NPPES side by side
NPPES | PECOS | |
|---|---|---|
What it is | CMS system that assigns and stores NPIs | CMS's online Medicare enrollment management system |
What it holds | Your NPI and the provider information tied to it | Your Medicare enrollment record |
What you do there | Apply for an NPI online (paper and bulk options also exist) | Enroll, review and update information, report changes, withdraw, upload documents, sign and submit |
Who uses the result | Health plans, including Medicare and private health plans | Medicare |
Who processes it | CMS maintains it | Your Medicare contractor processes applications |
How it relates to the other | Your NPI is reported on the Medicare application | Requires an NPI but is a separate process |
Common mix-ups
"I updated NPPES, so Medicare has my new details." Not automatically. CMS says updates to a provider's NPI record in NPPES do not automatically update the provider's Medicare enrollment information. If something changes, check each record on its own.
"Small differences between the two records don't matter." CMS's Medicare enrollment application (Form CMS-855I) says your name, Social Security number, legal business name, taxpayer identification number, and NPI must match exactly in PECOS and NPPES. (CMS-855I)
"I have an NPI, so I'm enrolled in Medicare." No. An NPI is required for Medicare enrollment, but obtaining one does not replace the enrollment process.
"The NPPES reporting rule covers PECOS too." It does not. The rule below is about NPPES data only: Under 45 CFR 162.410, covered health care providers must report changes to their required NPPES data within 30 days of the change. (eCFR, 45 CFR 162.410)
"The NPI is just for Medicare." Private health plans also require NPIs in their transactions.
Keeping both records current
Treat NPPES and PECOS as two records you check separately, since an NPPES update does not automatically update your Medicare enrollment information.
For NPPES, the federal reporting rule above applies. For PECOS, CMS keeps your enrollment active when you certify that you meet, and continue to meet, its requirements and CMS verifies that you do. PECOS is the place to review your information and report changes to your enrollment record.
For a broader look at how payer enrollment differs from credentialing, see credentialing vs payer enrollment.
For help with enrollment, see our provider enrollment service.
Related reading: How Long Does Credentialing Take? What CMS and Payers Publish.
FAQs
What is NPPES?
NPPES is the CMS system that assigns NPIs to health care providers and stores and manages them.
What is PECOS?
PECOS is CMS's online Medicare enrollment management system, where you enroll, review and update your information, and report changes to your enrollment record.
If I update NPPES, does PECOS update?
Not automatically. CMS says an NPPES update does not automatically update your Medicare enrollment information.
Who reviews a PECOS application?
Your Medicare contractor processes enrollment applications.
Not sure your NPPES and PECOS records match?
A credentialing audit is a preliminary review of where your credentialing stands. You receive a written report of the current issues we find with your credentialing.
Approval, effective dates, and processing timelines are outside our control.
See our Medicare PECOS enrollment help.
Sources
- CMS, Manage Your Enrollment (page last modified 03/04/2026)
- CMS, Enrollment Applications (03/04/2026)
- CMS, PECOS hub page (07/31/2026)
- CMS, NPI Fact Sheet (December 2024)
- eCFR, 45 CFR 162.410(a)(4) (point-in-time 2026-10-15)
- eCFR, 45 CFR 162.408 (2026-10-15)
- eCFR, 42 CFR 424.506(b)(1)(i) (2026-10-15)
- eCFR, 42 CFR 424.510 (2026-10-15)
- eCFR, 42 CFR 424.516(a) (2026-10-15)
- NPPES website
- CMS, CMS-855I Medicare Enrollment Application (form revision 05/23)