QUICK ANSWER: Which Los Angeles health system you can use depends on how you get your Medicare. With Original Medicare plus a Medigap policy, you can see any provider that accepts Medicare, with no network to check. With a Medicare Advantage plan, access depends on the plan’s network for that year and, with most HMO plans in California, on the medical group your primary doctor belongs to. Check your doctor, their medical group, and your hospital in the plan’s 2027 directory before you enroll or switch.

If you live in Los Angeles County, the Medicare question that matters most is usually not “which plan has the lowest premium.” It is: can I keep seeing my doctors at UCLA Health, Cedars-Sinai, Keck Medicine of USC, Providence, or Kaiser Permanente?

Los Angeles has more Medicare plan choices than almost any county in the country, and more large health systems competing for the same patients. That combination makes networks — not brochures — the deciding factor for most people. This guide explains how the county’s major health systems fit into Medicare, why the “medical group” line in a plan directory matters so much here, and exactly how to check before you enroll or make a change.

The health systems most Los Angeles beneficiaries use

Other systems many people rely on include Dignity Health, MemorialCare (Long Beach), Huntington Health (Pasadena), Torrance Memorial, PIH Health, and Adventist Health. Which of these you can use depends on how you receive your Medicare coverage.

Medicare Advantage in Los Angeles: the medical-group layer

Medicare Advantage (Part C) plans are offered by private insurers and typically use a network of local providers. In Los Angeles, most of these plans are HMOs, and HMOs in California add a layer that national websites rarely explain: you don’t just choose a plan — you (or the plan) also assign you to a medical group or IPA. That medical group, not the insurer, largely decides which specialists and hospitals you can use.

Los Angeles has some of the largest medical groups in the state — organizations such as Optum (formerly HealthCare Partners), Regal Medical Group, and the physician groups tied to the health systems above. Two neighbors on the identical plan can have very different access depending on which medical group each is assigned to. So when you check a plan, check three things:

  1. Is my doctor in the plan’s current directory?
  2. Which medical group is my doctor listed under in that plan?
  3. Does that medical group admit to the hospital I want — UCLA, Cedars-Sinai, Keck, Providence, or another?

Some Los Angeles systems are tied even more closely to a specific plan. One factual example: UCLA Health Medicare Advantage Plan is a Medicare Advantage HMO offered by UCLA Health, with a service area of Los Angeles County and enrollment that depends on annual contract renewal with Medicare. It is one option among many in the county; whether it, or any plan, fits you depends on your doctors, prescriptions, and budget. (This is a description, not a recommendation.)

Kaiser Permanente works differently again: its Medicare Advantage plans are built around Kaiser’s own doctors and facilities, so they generally suit people who want to receive their care within the Kaiser system.

Networks are not permanent — and Los Angeles has seen that recently. Providence announced on its own website that, effective January 1, 2026, the Providence Clinical Network — including Southern California medical groups such as Facey — would no longer be contracted with one large national insurer’s Medicare Advantage plans, while commercial plans were unaffected. According to the insurer’s own notice, the change applies to its individual Medicare Advantage HMO plans; Providence hospitals remain in network and employer group retiree plans were not affected. Changes like that are exactly why the Annual Notice of Change (ANOC) your plan mails each September deserves a careful read. Our guide to reading your Annual Notice of Change walks through what to look for, and if your plan is ending, see what to do when a Medicare Advantage plan is discontinued.

Original Medicare + Medigap: system choice without networks

If provider flexibility is your priority, the other route is Original Medicare with a Medicare Supplement (Medigap) policy. Medigap works alongside Parts A and B and lets you see any provider in the country that accepts Medicare — which includes the large Los Angeles systems for Medicare-participating services. There is no network to check and no medical-group assignment, and you can see a UCLA specialist one month and a Cedars-Sinai specialist the next.

The trade-offs: Medigap has its own monthly premium, and it doesn’t include drug coverage, so most people pair it with a standalone Part D plan. California also gives Medigap policyholders the Birthday Rule — a window of at least 60 days each year, starting on your birthday, to switch to another Medigap plan of equal or lesser benefits without medical underwriting.

For a fuller comparison of the two routes, see Medicare Advantage vs. Medicare Supplement.

How to check your doctors before you enroll or switch

  1. Make your list: every doctor you see, the hospital you’d choose, and your prescriptions with dosages.
  2. Use the plan’s current-year provider directory (online directories update more often than printed ones) and search each doctor by name.
  3. Note the medical group shown next to your primary doctor — then confirm your specialists are reachable through that same medical group.
  4. Check the health system’s own insurance page. UCLA Health, Cedars-Sinai, Keck Medicine of USC, and Providence each publish a list of accepted plans and medical groups; those pages often reflect contract changes before plan directories do.
  5. Call the doctor’s office and ask directly: “Which Medicare Advantage plans and medical groups are you accepting for next year?”
  6. Re-check every fall. Between October 15 and December 7 — the Annual Enrollment Period (AEP) — you can join, switch, or drop a Medicare Advantage or Part D plan for the following year. 2027 plan details are now in Medicare’s Plan Finder. Our Annual Enrollment guide for Southern California has a month-by-month checklist, and what’s changing in 2027 covers the numbers published so far.

If you’d rather not do this alone, this is exactly what an independent Medicare broker in Los Angeles County does: check your doctors, medical groups, and prescriptions against the plans I represent in your ZIP code, at no cost to you, because brokers are paid by the insurance carriers.

More local guides: how health systems work with Medicare in Los Angeles, Orange County, and San Diego.

Frequently asked questions

Does UCLA Health have its own Medicare Advantage plan?
Yes. UCLA Health offers the UCLA Health Medicare Advantage Plan, an HMO whose service area is Los Angeles County; its contract with Medicare renews annually. Other Medicare Advantage plans in the county may also include UCLA doctors through particular medical groups, so check each plan’s current directory.
Can I keep my Cedars-Sinai or Keck Medicine of USC doctor on Medicare Advantage?
It depends on the specific plan and medical group for the specific year. Both systems publish accepted-insurance pages, and participation can change annually, so verify your doctor and their medical group in the plan’s current directory or ask the office directly which plans they accept.
Which Medicare Advantage plans do UCLA Health, Cedars-Sinai, and Providence accept for 2027?
It depends on the specific plan and medical group, and it can change every year, so no single list stays accurate. 2027 plan details are now available in Medicare’s Plan Finder. Search for your doctor and their medical group in each plan’s 2027 provider directory, check the health system’s own insurance page, and ask the office directly which plans they will accept.
Do all Los Angeles hospitals accept Original Medicare?
The large Los Angeles systems participate in Original Medicare for covered, Medicare-participating services. With Original Medicare plus a Medigap policy, you can generally use any provider that accepts Medicare, without network restrictions.
What is a medical group, and why does it matter in Los Angeles?
With most California HMO plans, your primary doctor belongs to a medical group or IPA that coordinates referrals to specialists and hospitals. In Los Angeles, medical groups can be very large and can contract with some hospitals and not others, so the medical group, not just the plan name, determines where you can be treated.
What happens if my plan’s network drops my doctor or medical group?
Plans must notify you of significant changes. Your regular chance to change plans is the Annual Enrollment Period (October 15 – December 7); in some situations, such as certain significant network changes or a plan ending, Medicare may grant a Special Enrollment Period. Check with Medicare.gov or 1-800-MEDICARE about your specific situation.
Is it more expensive to get help from a broker when comparing Los Angeles plans?
No. Working with a licensed independent broker costs you nothing and doesn’t change your premium, because brokers are paid by the insurance carriers. You always remain free to compare every plan yourself at Medicare.gov.

Sources & official references

Last reviewed: October 2026. Educational information only, not individualized advice. Health-system, medical-group, and plan names are used for identification only and do not imply affiliation or endorsement. Plan networks and benefits change annually — confirm current details with the plan and at Medicare.gov. This is a non-government resource and is not affiliated with or endorsed by Medicare.gov or the federal Medicare program. We do not offer every plan available in your area. Currently we represent 12 organizations which offer 442 products in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options. For free, unbiased counseling, contact your local State Health Insurance Assistance Program (SHIP) — in California, the Health Insurance Counseling and Advocacy Program (HICAP), 1-800-434-0222. Matt Medicares Insurance is an independent insurance brokerage and is not affiliated with or endorsed by Medicare, the Centers for Medicare & Medicaid Services, or any government agency.