Form CMS-855I at a glance
What it is: CMS-855I is the Medicare Enrollment Application for Physicians and Non-Physician Practitioners.
Where and when to file: Send this completed application with original signatures and all required documentation to your designated MAC. The MAC that services your State is responsible for processing your enrollment application. To locate the mailing address for your designated MAC, go to CMS.gov/Medicare/Provider-Enrollment-and-Certification.
All physicians, as well as all eligible professionals as defined in section 1848(k)(3)(B) of the Social Security Act must complete this application to enroll in the Medicare program and receive a Medicare billing number (OMB No. 0938-1355, 05/26).
Physicians and non-physician practitioners can apply for enrollment in the Medicare program or make a change to their enrollment information (including adding or terminating a reassignment of benefits) using either the Internet-based Provider Enrollment, Chain and Ownership System (PECOS), or the paper CMS-855I enrollment application.
All reassignment actions should now be reported via the CMS-855I. The CMS-855R (Reassignment of Medicare Benefits) form has been discontinued.
What to bring and attach to Form CMS-855I
Completed Form CMS-588, Electronic Funds Transfer Authorization Agreement. Include a voided check or bank letter.
If you currently receive payments electronically and are not making a change to your banking information, the CMS-588 is not required.
Physicians and non-physician practitioners who are reassigning all of their payments to a group/clinic or other health care organization are not required to submit the CMS-588.
Completed Form CMS-460, Medicare Participating Physician or Supplier Agreement. The CMS-460 must be submitted for all initial enrollments or reactivations only if you want to be a Participating Practitioner in Medicare.
Attach all required supporting documentation.
A filled-in Form CMS-855I example: Dr. Sample fills in Section 2A

How to fill out Form CMS-855I, box by box
Section 1A: you are a new enrollee, reporting a change or terminating
Check one box and complete the sections of this application as indicated.
If you are a new enrollee in Medicare, complete all applicable sections.
If you are reporting a change to your Medicare enrollment information (includes establishing or terminating a reassignment), go to section 1B below.
If you are voluntarily terminating your Medicare enrollment: Sections 1A, 2A, 13 (optional), and 15.
Section 1B: what information is changing
Check all that apply and complete the required sections. When reporting ANY information, sections 1, 2A, 3 and 15 MUST always be completed in addition to the information that is changing within the required section.
Section 2D: Correspondence Mailing Address
Your Correspondence Mailing Address cannot be a billing agent or agency's address or a medical management company address.
Section 4B: Practice Location Information
You do not need to complete this section if you are reassigning 100% of your Medicare benefits.
Complete this section for each of your practice locations where you render services to Medicare beneficiaries, including any distant site(s) where you render telehealth services.
All reported practice location addresses must be a specific street address as recorded by the United States Postal Service. Your practice location must be the physical location where you render services to Medicare beneficiaries. Your practice location address cannot be a Post Office (P.O.) Box.
Only report those practice locations that are within the jurisdiction of the designated MAC to which you will be submitting this application. If you have to report practice locations outside the jurisdiction of the designated MAC to which you are submitting this application you must submit a separate CMS-855I Enrollment Application to the MAC that has jurisdiction for those locations.
Section 15: certification statement and signature
As an individual practitioner, you are the only person who can sign this application. The authority to sign the application on your behalf may not be delegated to any other person (CMS-855I 05/23, Section 15, 23).
You MUST sign and date the certification statement in order to be enrolled in the Medicare program.
In order to process this application it MUST be signed and dated.
More rules for Form CMS-855I
This form must be typed. It may not be handwritten.
All information on this form is required with the exception of those fields specifically marked as “optional.” Any field marked as optional is not required to be completed nor does it need to be updated or reported as a “change of information” as required in 42 C.F.R. section 424.516.
Keep a copy of your completed Medicare enrollment package for your own records.
If your situation is different
When establishing or terminating a reassignment, or making changes to reassignment information
When establishing a new reassignment, Section 15B must be signed by the individual practitioner and Section 15C must be signed by a delegated/authorized official of the organization/group. If the reassignment is to an individual, that person must sign Section 15C.
When terminating a reassignment or making changes to reassignment information, either the organization/group must sign Section 15C or the individual practitioner must sign Section 15B.
Common questions about Form CMS-855I
Is there a deadline?
If the MAC requests additional documentation to support and validate information reported on this application, you are responsible for providing this documentation within 30 days of the request per 42 C.F.R. section 424.525(a)(1) and (2).
Where do I file it?
Send this completed application with original signatures and all required documentation to your designated MAC.
Is there a penalty?
18 U.S.C. 1035 authorizes criminal penalties against individuals in any matter involving a health care benefit program who knowingly and willfully falsifies, conceals or covers up by any trick, scheme, or device a material fact. The individual shall be fined or imprisoned up to 5 years or both.
When is this form not the right one?
If you are a sole owner and intend to add an Authorized/Delegated Official to your Medicare enrollment, do not complete the CMS-855I application; rather, use the CMS-855B application.
Sources
[1] Form CMS-855I (05/23), Medicare Enrollment Application, Physicians and Non-Physician Practitioners, Centers for Medicare & Medicaid Services (the Official source link on this page).
