Medicare credentialing, which CMS calls enrollment, happens in PECOS, and the Medicare Administrative Contractor (MAC) for your region decides whether to approve it. Get the application right and you can bill Medicare. Get it wrong and the MAC sends it back with a request for more information that you have 30 days to answer.
This guide covers the forms, the documents, the steps in PECOS, what to expect on timing, and the rules that keep your enrollment active once you are approved. If you are weighing participating status, Medicare Advantage, or opting out, our companion post on getting in-network with Medicare picks up where this one stops.
Key Takeaways
- Medicare enrollment runs through PECOS, and the MAC for your practice region reviews the application.
- Most physicians and non-physician practitioners start with the CMS-855I.
- Respond to any MAC request for information within 30 days, or the application can be rejected.
- CMS does not publish a single processing time, so plan for a few months and track the application.
- Report ownership changes, practice location changes, and adverse legal actions within 30 days. Report everything else within 90 days.
- Revalidate about every five years, and do not ignore the notice. Missing it can mean deactivation.
What Medicare Credentialing Means
Commercial payers credential you and then contract with you. Medicare works differently. You enroll with CMS, and the MAC for your practice region processes the request, verifies your information, and assigns you a Provider Transaction Access Number (PTAN) when you are approved. The rules are federal, so the process is the same across states, unlike Medicaid.
Our overview of medical credentialing explains how this differs from commercial credentialing. CMS also lays out the basic steps on its page for becoming a Medicare provider or supplier.
What to Have Ready Before You Start
Most delays start with a missing document, so gather these first.
- Your National Provider Identifier. If you do not have one, our post on the National Provider Identifier explains how to get one through NPPES.
- Current state license for every state where you will treat Medicare patients
- Medical degree, residency, and fellowship records
- DEA registration, if you prescribe controlled substances
- Board certification, if you hold it
- Malpractice insurance details
- Your TIN or EIN, and a decision on which one you will bill under
- Practice location details, including a physical address where you see patients
- Disclosures for any sanctions, exclusions, license actions, or malpractice judgments
Disclose everything that applies, even if it was minor or resolved in your favor. The MAC runs its own checks, and an omission looks worse than the event.
Which Form and Who Enrolls
Individuals and organizations enroll separately. CMS says most physicians and non-physician practitioners complete the CMS-855I to start. Group practices and other organizations use the CMS-855B, and ordering or certifying-only providers use the CMS-855O. The reassignment form, CMS-855R, has been merged into the CMS-855I paper application.
If you work for a group, the group has its own enrollment, and you reassign your billing rights to it. A solo practitioner who operates through a professional corporation or LLC usually enrolls as an individual and as an organization. Organizations use the Identity and Access (I&A) system to name an Authorized Official, who signs for the group. For a closer look at the system itself, read our post on what PECOS 2.0 changed.
Applying in PECOS Step by Step
CMS recommends applying online through PECOS. A paper application is for people who cannot apply online.
- Get your NPI from NPPES, or confirm the one you already have in the NPI Registry.
- Set up your I&A access and open PECOS.
- Enter your information exactly as it appears on your license and other records. Name mismatches are a common source of delays.
- Add your practice location, ownership and control details, and reassignment information if you bill through a group.
- Upload your documents and sign.
- Pay the application fee if the CMS Application Fee Matrix says one applies to you.
- Submit, then watch for MAC requests.
PECOS lets you save your progress, but do not let a draft sit for weeks. The sooner you submit a complete application, the sooner the MAC can start.
Screening and Site Visits
The MAC verifies your credentials and screens you against federal exclusion lists. CMS also says its National Site Visit Contractor conducts unannounced site visits for all Medicare Part A and B providers and suppliers. A visit may be a quick observation or a detailed review, so your practice location must be a real place where you see patients, with staff or signage that matches your application.
How Long Medicare Credentialing Takes
CMS does not publish a single processing time on its provider enrollment pages. The 60 to 90 days quoted in many guides is a rule of thumb. Clean applications move faster, and timing varies by MAC and provider type.
Our average credentialing turnaround across payers is about 85 days, which is a useful yardstick for planning. Build in time for a request for information, a possible site visit, and the weeks it takes outside parties to respond.
Checking Status and Answering the MAC
Your MAC can tell you where your application stands, and CMS links to a contact list for each MAC. If the MAC asks for more information, respond within 30 days. CMS says failure to respond may lead the MAC to reject the application, and starting over costs you weeks.
Keep a simple log of what you submitted, when, and what the MAC asked for. When you answer a request, send everything it asked for in one response.
Enrolling in More Than One State
Your MAC is based on your practice region, so locations in different regions may be handled by different MACs. You also need a license in each state where you treat patients. Your core information stays the same, and you mostly add the new locations and licenses.
Telehealth adds a wrinkle, since it depends on where you and the patient are located. Our posts on state-by-state credentialing requirements and telehealth credentialing cover that in more detail.
Revalidation and Reporting Changes
Physicians and most other providers revalidate about every five years, though CMS can ask for an off-cycle revalidation. Your MAC sends a notice by email or mail about three to four months before your due date, but CMS says tracking the date is your job. The CMS revalidation page points to a lookup tool that lists due dates, and CMS posts them seven months ahead.
Submit within three months of your due date, even without a notice. Do not submit more than seven months early without one, because CMS returns unsolicited revalidations. Missing the deadline can lead to a payment hold or deactivation of your billing privileges, and CMS does not grant extensions. After deactivation you must file a full new application.
Between revalidations, report a change of ownership or control, a change in practice location, and any final adverse legal action within 30 days. Report all other changes within 90 days.
Participation Status and Medicare Advantage
Approval does not decide your participation status. CMS gives you 90 days after your initial approval letter to choose, and the choice affects your fee schedule and balance billing. That topic, along with opting out, is covered in the in-network post linked near the top of this guide.
Original Medicare enrollment also does not put you in any Medicare Advantage network. Those plans are run by private insurers, and each credentials on its own. If you expect Medicare Advantage patients, see our guides to credentialing with Anthem, Aetna, Cigna, UnitedHealthcare, and Kaiser Permanente.
Common Medicare Enrollment Mistakes
A handful of errors cause most of the trouble.
- An incomplete application, such as missing signatures, empty sections, or absent documents.
- Inconsistent information. Names, dates, and addresses must match across PECOS and your records.
- Leaving out required disclosures.
- Letting a license or DEA registration expire while the application is pending.
- Missing the 30-day deadline to answer a MAC request.
- Forgetting the revalidation date years later.
The process shifts at Optum, and we cover those differences in our guide.
Get Credentialed with Medicare FAQ
What is Medicare credentialing?
Medicare credentialing is the enrollment process CMS uses to authorize a provider to bill Medicare for covered services. The provider applies through PECOS, and the Medicare Administrative Contractor for the practice region reviews and processes the application.
What system do I use to apply for Medicare enrollment?
PECOS, the Provider Enrollment, Chain and Ownership System. CMS recommends applying online, and a paper application is available only if you cannot apply online.
Which Medicare enrollment form should I use?
Most physicians and non-physician practitioners start with the CMS-855I. Group practices and other organizations use the CMS-855B, and ordering or certifying-only providers use the CMS-855O.
How long does Medicare credentialing take?
CMS does not publish one processing time. Plan for a few months, and expect clean applications to move faster than ones that need corrections or a site visit.
How long do I have to answer a MAC request for information?
You have 30 days. CMS says failing to respond may lead the MAC to reject the application.
How often do I need to revalidate my Medicare enrollment?
Most providers revalidate about every five years, and CMS can request an off-cycle revalidation. The MAC sends a notice three to four months before the due date, and a missed deadline can lead to a payment hold or deactivation.
How quickly do I have to report changes to Medicare?
Within 30 days for a change of ownership or control, a change in practice location, or a final adverse legal action. Other changes are due within 90 days.
Does Medicare enrollment make me part of Medicare Advantage networks?
No. Medicare Advantage plans are run by private insurers and credential providers on their own, so you need to apply to each plan separately.
Summary: Letting Medwave Handle Medicare Enrollment
Medicare enrollment rewards a complete PECOS application, a quick answer to every MAC request, and a calendar entry for revalidation. Most problems come from a missing document or a deadline nobody tracked.
At Medwave, we handle billing, credentialing, and payer contracting for practices, which includes preparing the PECOS application, tracking it with your MAC, and managing revalidation. Your medical billing and payer contracting depend on that enrollment being right, and our video on credentialing with Medicare and Medicaid shows how we approach it. Contact us below to start your Medicare enrollment.
Co-Founder and COO of Medwave, bringing more than 25 years of hands-on experience in healthcare revenue cycle management, payer contracting, and medical credentialing.