Introduction to Medicare's Parts

Medicare has four main parts – A, B, C and D.

  • Parts A and B are often referred to as "Original Medicare" or "Traditional Medicare." This is a fee-for-service health plan operated by the federal government.
  • Part C is called a Medicare Advantage Plan or Medicare Health Plan. These plans are purchased through private insurance companies.
  • You also have the option of getting prescription drug (Part D) coverage and additional coverage called Medicare Supplement Insurance (Medigap).

You must be enrolled in Parts A and B to sign up for Parts C or D.

Medicare's Parts in Detail

  • Covers hospital stays, skilled nursing facilities, some home-health services and hospice care.
  • Medicare pays an approved amount for each type of care.
  • There is no monthly premium, but you must pay a yearly deductible before Medicare will cover hospital costs.
  • You are eligible to enroll in Part A starting three months before the month of your 65th birthday, during the month of your 65th birthday, and in the three months after your 65th birthday month.

Medicare Part A covers care at Cedars-Sinai Medical Center and Marina Del Rey Hospital.

  • Covers doctor visits, some home-health services, laboratory tests, X-rays and other outpatient care, including some medical supplies and equipment.
  • This is optional coverage and requires that you pay a monthly premium.
  • You’re eligible to enroll in Part B starting three months before the month of your 65th birthday, during the month of your 65th birthday, and in the three months after your 65th birthday month.
  • If you opt out of Part B during this initial enrollment period, then decide to enroll at a later date, you may have to pay a higher premium. Your monthly premium for Part B may go up 10 percent for each year you were eligible for but did not enroll in Part B.

Medicare Part B covers care from Cedars-Sinai, Marina Del Rey Hospital and many of our physicians.

  • Part C, also known as Medicare Advantage or a Medicare Health plan, is purchased from a private insurance company and typically organized like an HMO or PPO insurance plan.
  • Part C puts coverage from both Part A and Part B into one plan. Most of these plans also include Medicare Part D drug coverage.
  • Cedars-Sinai participates in the following Medicare Advantage plans:
    • Blue Shield 65 Plus HMO
    • CareMore HMO and HMO Special Needs Plans
    • UnitedHealthcare Medicare Advantage HMO (AARP MedicareComplete SecureHorizons)
      • Premier Plan
      • Plans 1 and 3
      • Essential Plan

If you're enrolled in these plans, you must choose a primary care doctor in either the Cedars-Sinai Medical Group or Cedars-Sinai Health Associates and be referred to specialists within these groups. These plans have options that include Part D coverage.

  • Covers prescription drugs.
  • This is optional coverage and requires that you pay a monthly premium, and possibly a deductible and copays for your medications.
  • Most Medicare Advantage (Part C) plans include Part D coverage.
  • You should review a plan’s formulary and compare prices for the drugs you need when shopping for Part D coverage.
  • If you have health insurance through your employer, you should receive a letter letting you know whether your health plan meets the minimum government requirements. If it doesn’t, you’ll need to sign up for Part D coverage.

If you want prescription drug coverage, it is mandatory that you sign up for Part D as soon as you are eligible for Medicare Parts A and B. If you don’t sign up, you will be charged a penalty of 1 percent of the national average premium cost for Part D coverage based on the number of months you didn’t have drug coverage.

Other Medicare Options to Consider

Medical supplement insurance—also called "Medigap"—is a plan that pays some of Medicare’s out-of-pocket costs such as copays and deductibles and certain non-covered services. You must have Medicare Parts A and B to buy a Medigap policy. People with Medicare Advantage plans, however, do not need and cannot use Medigap policies.

Your Younger Spouse

If your younger spouse is covered by your employer-provided health insurance and will be losing that coverage as you retire, he or she will have a window of time during which they can enroll in a new plan through the Covered California exchange, an insurance broker or directly from an insurance company.

Need Help?

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Effective July 1, 2017, California has implemented consumer protection laws protecting patients from receiving "surprise bills" from physicians in certain circumstances when a physician is providing services at an in-network facility. If Cedars-Sinai is considered in-network and a physician is out of network and providing non-emergent services, unless receiving prior consent, the physician might be legally restricted in the amount he/she can bill patients beyond what a patient would expect under the terms of their commercial health plan. The law is complex and there are several exceptions to the rules. If you have questions or complaints, please contact the California Department of Managed Health Care at 888-466-2219.

Medicare Enrollment

See the different enrollment periods, including initial, special and open, and figure out when you can enroll.


Get definitions to terms, abbreviations and acronyms related to billing, insurance and financial assistance.

Coverage for Beneficiaries

Get details about the program at Cedars-Sinai, which includes both traditional and Advantage plans.