Who Qualifies for Medicare? Eligibility Requirements Explained

To qualify for Medicare, you must be 65 or older, or under 65 with a qualifying disability, end-stage renal disease (ESRD) or amyotrophic lateral sclerosis (ALS). Medicare is the federal health insurance program for U.S. citizens and qualifying legal residents. Unlike Medicaid, eligibility doesn't depend on your income. Two baseline requirements apply to all enrollees regardless of age or disability status: U.S. citizenship or qualifying legal residency. 

• U.S. citizenship: You must be a U.S. citizen. Lawful permanent residents must also meet the five-year residency requirement.
• Legal residency: Lawful permanent residents must have lived continuously in the United States for at least five consecutive years immediately before applying for Medicare.

Medicare covers people under 65 who receive Social Security Disability Insurance (SSDI) or qualify through specific medical conditions. Eligibility paths vary by condition: some require a waiting period, others don't. You apply through the Social Security Administration, which determines disability status and administers SSDI benefits. Medicare itself does not make eligibility determinations.

Adults under 65 without SSDI, ESRD or ALS don't qualify for Medicare, regardless of income or insurance history. Non-citizens with fewer than five consecutive U.S. residency years are also excluded. Low income alone doesn't qualify you. Medicaid covers income-eligible people. Medicare and Medicaid are separate federal programs with different eligibility rules.

Medicare Part A covers inpatient hospital stays, skilled nursing facility care, hospice and some home health services. You qualify for Part A in three ways. About 99% of Medicare beneficiaries pay nothing for Part A, per CMS, because they or their spouse paid Medicare taxes for at least 10 years.

Medicare Part B covers outpatient care, doctor visits, preventive services and medically necessary services. If you qualify for premium-free Part A, you're also eligible for Part B. The standard 2026 Part B monthly premium is $202.90, per CMS. (40 words)

If you don't have premium-free Part A, you can still enroll in Part B if you meet all three of these conditions: 

• You're at least 65 years old
• You're a U.S. resident
• You're a U.S. citizen, or a lawful permanent resident who has lived in the United States continuously for at least five years before applying 
  

Part B enrollment isn't automatic for everyone. Without Social Security or RRB benefits before turning 65, you must apply during your Initial Enrollment Period. Missing it means waiting for the General Enrollment Period (January 1 to March 31), with coverage starting July 1. The late enrollment penalty is permanent and lasts as long as you have Part B.

You can still get Medicare without 40 quarters of work history, but Part A won't be premium-free. Part B also requires a monthly premium regardless of work history. CMS updates both premiums annually. Your Part A premium depends on how many work quarters you or your spouse accumulated under Social Security, the Railroad Retirement Board or Medicare-covered government employment.

If you reach 40 work quarters while still employed, your Part A premium drops to $0. Part B's $202.90 monthly standard premium applies to most enrollees in 2026. Higher-income enrollees pay more: if your 2024 reported income exceeded $109,000 (individual) or $218,000 (joint), you pay an Income-Related Monthly Adjustment Amount (IRMAA) on top of the standard Part B premium, per CMS.

Medicare Part C, also called Medicare Advantage, is an alternative to Original Medicare offered by CMS-approved private insurers. You must have both Medicare Part A and Part B and live in the plan's service area to qualify.   

• Medicare Advantage plans vary by ZIP code. Confirm doctors and hospitals are in-network before enrolling. PPO plans cover out-of-network providers at higher cost-sharing than in-network care.
• Since 2021, people with ESRD can also enroll in Medicare Advantage, a change that expanded access for those with permanent kidney failure.
• Compare plans at medicare.gov.

Medicare Part D covers prescription drug costs. You qualify for Part D if you're enrolled in Medicare Part A, Part B or both. Part D plans are offered by private insurance companies approved by Medicare, and plan availability varies by location.

Medicare eligibility covers more Americans than many expect: seniors turning 65, younger adults with SSDI, ALS or ESRD, and anyone with at least 40 work quarters. Your coverage path depends on age, work history and health status. Signing up during your Initial Enrollment Period is important as Part B late penalties are permanent. Compare your Part A, B, C and D options before your 7-month window closes.

We've answered the most frequently asked questions about Medicare's enrollment rules and work history requirements: