Section 1: Basic information
The reason for submitting (enrolling, updating or withdrawing) and the reason for enrolling solely to order/certify, chosen from Group 1 or Group 2.
CMS-855O
Medicare Enrollment Application - Registration For Eligible Ordering and Referring Physicians and Non-Physician Practitioners
- Agency
- CMS
- Revision
- 09/23
- Fillable fields
- 174
- Pages
- 11
- Official source
- CMS form page
- Checked
- October 20, 2026
Form CMS-855O: Medicare Enrollment Application for Ordering/Certifying Physicians
Form CMS-855O is the Medicare Enrollment Application for Eligible Ordering/Certifying Physicians and Other Eligible Professionals from the Centers for Medicare & Medicaid Services (CMS). The form says physicians and eligible professionals use it to enroll for the sole purpose of ordering or certifying items and/or services for Medicare beneficiaries, or to change their ordering/certifying enrollment information. It says they do not and will not send claims to a Medicare Administrative Contractor (MAC) for the services they furnish.
The application has eight sections: basic information and the reason for enrolling, identifying information with education, licenses, certifications and DEA registration, final adverse legal actions, medical specialty, a correspondence address, an optional contact person, penalties for falsifying information, and the certification statement and signature. The CMS forms page lists it as Registration for Eligible Ordering and Referring Physicians and Non-Physician Practitioners.
The form says the same enrollment can be done online through PECOS, the Internet-based Provider Enrollment, Chain and Ownership System, and that the paper form is to be typed, not handwritten. You can type it free in your browser on this page and download the result without an account.
What's on Form CMS-855O
Section 2: Identifying information
Name, other names, SSN, date of birth, gender, PTAN if issued, Type 1 NPI, whether you owe an existing debt to CMS, professional school and graduation year, and active license, certification and DEA registration details.
Section 3: Final adverse legal actions
Federal and state convictions within the preceding 10 years, exclusions, revocations or suspensions, and a history table with each action, its date and who took it. The form says to report them regardless of expunged records or pending appeals.
Section 4: Medical specialty
One primary physician specialty from the list in 4A, or one eligible professional or non-physician specialty in 4B, such as nurse practitioner, physician assistant or clinical psychologist.
Sections 5 and 6: address and contact person
The correspondence mailing address the MAC uses, which the form says cannot be a billing agent's or medical management company's address, and an optional contact person the MAC may reach about this application.
Sections 7 and 8: penalties and signature
Penalties for falsifying information, then the certification statement signed and dated by the practitioner. The form says the authority to sign may not be delegated.
The form says all information is required except fields marked optional.
How to submit Form CMS-855O
- 1
Get an NPI first
The form says the NPI comes from NPPES in a process separate from Medicare enrollment and is reported on this application. It can be requested online at NPPES.cms.hhs.gov.
- 2
Pick your reasons in Section 1
Check one box in 1A, which also says which sections to complete, and one reason from Group 1 or Group 2 in 1B.
- 3
Match your social security record
Section 2A says the name, date of birth and SSN given match the social security record. The tips page also asks for the NPI in section 2.
- 4
Complete sections 2 to 6
Add education, license, certification and DEA details, any final adverse legal actions, one specialty in section 4 and the correspondence address in section 5. Section 6 is optional.
- 5
Type it and sign section 8 in ink
The form says it is to be typed, not handwritten, and the tips page says to sign and date section 8 using ink. Only the individual practitioner can sign.
- 6
Send it to your MAC
Send the application with original signatures and all required documentation to your designated MAC, or enroll through Internet-based PECOS instead.
Why fill Form CMS-855O on indox
You get the real form, filled in a browser tab, with nothing standing between you and the finished PDF.
- Fill the form right in your browser, no software to install
- Free to fill and free to download, with no account
- The official blank straight from the CMS, not a copy someone retyped
- Works on a phone, tablet or computer
Where it goes, timing and help
Where to send it
To your designated MAC, the one that services your state. The form points to CMS.gov/Medicare/Provider-Enrollment-and-Certification for the MAC's mailing address, and says not to mail applications to the CMS address in its Paperwork Reduction Act notice.
Online instead
The form says enrollment and changes can be made with the CMS-855O application on Internet-based PECOS or on paper.
Requests for more documents
The form says the MAC may request more documentation and that it is due within 30 days of the request, citing 42 C.F.R. section 424.525(a)(1).
Penalties
Section 7 lists criminal and civil penalties for deliberately furnishing false information, citing laws such as 18 U.S.C. section 1001, section 1128B(a)(1) of the Social Security Act and the Civil False Claims Act.
Form version
The form shows OMB No. 0938-1135 and Expires: 05/26, and says to be sure you are using the most current version. The CMS page lists a revision date of 2023-09-01.
Time to complete
The form estimates 30 minutes per response, including reviewing instructions and gathering the data.
Related forms
CMS-855I
Medicare Enrollment Application - Physicians and Non-Physician Practitioners
513 fields, 26 pages
CMS-855B
Medicare Enrollment Application - Clinics/Group Practices and Certain Other Suppliers
960 fields, 54 pages
CMS-855A
Medicare Enrollment Application - Institutional Providers
1,236 fields, 72 pages
CMS-855S
Medicare Enrollment Application - Durable Medical Equipment, Prosthetics, Orthotics, and Supplies (DMEPOS) Suppliers
1,031 fields, 39 pages
CMS-20134
Medicare Enrollment Application - Medicare Diabetes Prevention Program (MDPP) Suppliers
323 fields, 31 pages
Who uses Form CMS-855O?
Page 1 says the list of who may enroll solely to order/certify includes, but is not limited to, the groups below.
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Questions about Form CMS-855O
Can I bill Medicare after enrolling with Form CMS-855O?
The form says CMS-855O enrollees do not and will not send claims to a MAC for the services they furnish. Certification item 1 says a practitioner who wishes to be reimbursed by Medicare first enrolls as an individual supplier using the CMS-855I.
Who can enroll with Form CMS-855O?
Page 1 lists, among others, physicians and eligible professionals employed by the DVA, DOD/Tricare, PHS, IHS or a Tribal Organization, or an FQHC, RHC or CAH, plus licensed residents, dentists including oral surgeons, pediatricians and retired physicians who are licensed.
Can Form CMS-855O be handwritten?
No. The instructions say the form is to be typed and may not be handwritten, and that the MAC may return an application with handwritten portions.
Can I enroll online instead?
The form says the same enrollment or change can be made with the CMS-855O application on Internet-based PECOS. You can also fill out the PDF here free and download it.
Who signs Form CMS-855O?
The form says the individual practitioner is the only person who can sign, the authority may not be delegated, and the application is processed only when signed and dated.
Where do I send Form CMS-855O?
To your designated MAC with original signatures and all required documentation. The form points to CMS.gov/Medicare/Provider-Enrollment-and-Certification for the MAC's mailing address.
What happens once enrolled?
The form says enrollees are listed on a CMS database and deemed eligible to order/certify services and items for Medicare beneficiaries.