US · guidance
CMS Pub. 100-16, ch. mc86c17d, § 60.1.1
Enrollment Retroactive to Date of Initial Medicare Entitlement
The effective date of membership as a Medicare beneficiary is the month in which the
individual becomes entitled to benefits under Medicare Part A and is enrolled in
Medicare Part B, or enrolled in Medicare Part B only if:
• The individual enrolls in Part B of Medicare and applies to the cost plan prior to
the month in which he/she is entitled to part B of Medicare; or
• The individual is a member of the cost plan organization prior to his/her
entitlement to Medicare benefits and applies to the cost plan prior to the month of
entitlement.
Some beneficiaries may not have a record of entitlement to Part B established in the data
system at CMS until after the actual date of first entitlement. In such cases, CMS will
take action to correct the effective date retroactively.
History
(Rev. 38, 10-31-03)
Provenance
- Source
- cms.gov
- Retrieved
- 2026-08-25
- Edition
- iom-2026-08-25
- Content hash
8df81351a953038b3610bd2d467bf32e0e91db82b83f914b6debe812afe6839f
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