Medicare CMS-855 Prep

Plain-language guide aligned with CMS: 855I, 855O, 855A — reassignment via Section 4F (not discontinued 855R)

Use public NPPES, PECOS, and OIG data to choose the right CMS form (855I, 855O, or 855A), see readiness gaps, and gather Section 12 documents. Reassignment uses CMS-855I Section 4F—the discontinued CMS-855R form is not used.

Reference information only. Not medical, legal, or immigration advice. Not official CMS guidance. Full disclaimer

Enter an NPI to see which CMS form applies, your readiness score, a field map from NPPES, and a Section 12 document checklist. CMS discontinued form CMS-855R in 2023. Reassignment is reported on CMS-855I Section 4F or in PECOS. CMS PECOS

CMS enrollment resources

PECOS — Medicare Provider Enrollment
Official CMS system to enroll in Medicare after you have an NPI. Separate from NPPES NPI assignment.
Medicare Enrollment
PECOS Provider Resources
Forms, guides, and help for Medicare enrollment (CMS-855 series), not for initial NPI enumeration.
Medicare Enrollment
CMS-855I — Physicians and Non-Physician Practitioners (PDF)
Medicare enrollment application for individual practitioners billing fee-for-service.
Medicare Enrollment
CMS-855O — Ordering and Referring (PDF)
Enrollment for physicians who order and refer but do not bill as rendering providers.
Medicare Enrollment
CMS-855B — Medicare health plans / DMEPOS (PDF)
Enrollment for certain organizations (e.g. Medicare health plans, DMEPOS)—not for individual reassignment. Reassignment uses CMS-855I Section 4F.
Medicare Enrollment
CMS bulletin — CMS-855R merged into CMS-855I
Official notice that CMS-855R was discontinued and reassignment is reported on CMS-855I (effective 2023).
Medicare Enrollment
CMS-855A — Medicare Enrollment Application (PDF)
Enrollment application for Medicare suppliers and organizations (Type 2 NPI).
Medicare Enrollment
Medicare CMS-855 Prep (usnpi)
Readiness score, field map, and Section 12 checklist before PECOS enrollment.
usnpi Tools

View full list of official sources →

Source: CMS public data · Not endorsed by CMS ·

This tool does not submit applications to CMS. Tools disclaimer

Last reviewed May 2026