CMS's own filing for California
Medicare Advantage plans in California, by the numbers
What CMS published about Medicare enrollment in California: 5 of 5 measures filed for this state, each one a field of the state's own row with the date the file was read.
- figures published by CMS
- 5
- counts CMS withheld
- 0
- the day this file was read
- 2026-09-11
Where California sits among the states
51.2% of everyone with Medicare in California is in a Medicare Advantage or other health plan rather than Original Medicare. That puts California 25th of 51, between Nevada above it and Arizona below. Across the country the same figure runs from 62.8% in Michigan down to 3.0% in Alaska, so what counts as the ordinary choice depends on where a person lives, and this is what it is where they do.
Every measure CMS filed for California
| Measure | What CMS published | Source |
|---|---|---|
| People with Medicare | In 2025, 7,108,792 people were enrolled in Medicare in California. | CMS Medicare Monthly Enrollment, 2025 read September 2026 |
| In Medicare Advantage and other health plans | In 2025, 3,640,439 of them were in Medicare Advantage or another health plan rather than Original Medicare in California (51.2% of everyone with Medicare in California). | CMS Medicare Monthly Enrollment, 2025 read September 2026 |
| In Original Medicare | In 2025, 3,468,354 stayed in Original Medicare in California (48.8% of everyone with Medicare in California). | CMS Medicare Monthly Enrollment, 2025 read September 2026 |
| In a stand-alone Part D drug plan | In 2025, 2,403,799 bought drug coverage as a stand-alone Part D plan in California (33.8% of everyone with Medicare in California). | CMS Medicare Monthly Enrollment, 2025 read September 2026 |
| Also covered by Medicaid | In 2025, 1,779,175 were covered by Medicaid as well as Medicare in California (25.0% of everyone with Medicare in California). | CMS Medicare Monthly Enrollment, 2025 read September 2026 |
A withheld figure means CMS did not publish the count, never that the count is zero.
Cite or embed this figure
California: 5 Medicare enrollment figures published by CMS and 0 counts withheld (Medicare Plan Comparison State Enrollment Index).
Cite as: "Medicare Plan Comparison State Enrollment Index: California", updated 2026-09-11, https://medicareplancomparison.com/states/california/.
Download the California figures (CSV), free to reuse with citation.