Medicaid: Eligibility, Benefits, and How to Enroll

Medicaid is the largest source of health coverage in the United States, insuring more than 84 million people as of 2023 (Medicaid.gov enrollment data). It operates as a joint federal-state program, which means the rules — who qualifies, what's covered, how to apply — vary meaningfully depending on which state someone lives in. This page covers the eligibility framework, what benefits the program provides, how enrollment actually works, and the specific situations where Medicaid decisions get complicated.

Definition and scope

Medicaid was established in 1965 under Title XIX of the Social Security Act, running alongside Medicare from the start — but serving a fundamentally different population. Where Medicare is primarily an age-based entitlement, Medicaid is income- and category-based. The federal government sets minimum standards, provides matching funds, and the states administer the program. That federal-state split is why a 35-year-old parent in Louisiana may qualify under rules that would exclude the same person in Texas.

The program covers four broad groups: low-income adults, children, pregnant individuals, and people with disabilities or certain chronic conditions. Under the Affordable Care Act's Medicaid expansion — which 40 states and the District of Columbia had adopted as of 2024 (Kaiser Family Foundation, Status of State Medicaid Expansion) — eligibility for adults extends to anyone with household income at or below 138% of the Federal Poverty Level, regardless of whether they have children.

In the 10 non-expansion states, the older categorical rules still apply, meaning a childless adult with very low income may not qualify at all — a gap that affects an estimated 1.5 million people, according to the Kaiser Family Foundation.

How it works

Federal law, through 42 CFR Part 430–456, defines what states must cover and what they may cover as optional benefits. The federal government reimburses each state at a rate known as the Federal Medical Assistance Percentage (FMAP), which ranges from 50% to over 75% depending on a state's per-capita income — lower-income states receive a higher federal match (Medicaid.gov FMAP overview).

Mandatory federal benefits every participating state must provide include:

  1. Inpatient and outpatient hospital services
  2. Physician services
  3. Laboratory and X-ray services
  4. Early and Periodic Screening, Diagnostic, and Treatment (EPSDT) services for children under 21
  5. Family planning services and supplies
  6. Federally qualified health center (FQHC) services
  7. Nursing facility services for adults
  8. Home health care for those entitled to nursing facility services

Optional benefits — which most states include in some form — extend to prescription drugs, dental care, vision, physical therapy, and personal care services. Long-term care, including nursing home coverage, is one of Medicaid's most significant functions; it pays for nearly half of all long-term care spending in the United States (CMS National Health Expenditure data).

Delivery happens primarily through managed care organizations under contract with states, or through traditional fee-for-service arrangements, or both — depending on the state and the population served.

Common scenarios

Low-income families with children. Families earning below a state-set income threshold (often 100–138% FPL for parents, higher for children under CHIP) qualify in all 50 states. Children are broadly protected; in most states, children qualify up to at least 200% FPL under CHIP or Medicaid.

Pregnancy. Medicaid covers pregnancy-related care in every state, often at higher income thresholds than standard adult eligibility. Postpartum coverage — historically ending at 60 days — was extended to 12 months in states that chose the option under the American Rescue Plan Act of 2021, and 47 states had adopted that extension by 2024 (KFF Postpartum Coverage Tracker).

People with disabilities. Individuals receiving Supplemental Security Income (SSI) are automatically eligible in most states. Medicaid also operates waiver programs — authorized under Section 1915(c) of the Social Security Act — that fund home and community-based services as an alternative to institutional care.

Older adults and long-term care. Medicaid becomes the payer of last resort for nursing home care once a person's assets are spent down to state-defined limits. Asset transfer rules and look-back periods (typically 5 years) exist specifically to prevent strategic divestment before applying.

Decision boundaries

The biggest fork in eligibility logic is expansion vs. non-expansion. In expansion states, the income test is the primary gate. In non-expansion states, categorical membership (parent, pregnant, disabled, elderly) is required in addition to income.

A second key boundary: Medicaid vs. Marketplace plans. Households between 100% and 400% FPL in non-expansion states may qualify for Marketplace subsidies that they would not receive if their state had expanded Medicaid — a technical quirk worth understanding when comparing healthcare coverage options.

Application pathways differ by circumstance:

For people navigating the broader landscape of US healthcare coverage, Medicaid is often the first program to assess — because if income-based eligibility is met, it typically results in lower out-of-pocket costs than subsidized Marketplace plans.

The National Healthcare Authority home provides a broader orientation to the US system for those approaching these questions for the first time.

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