Reviewed August 7, 2026

Sign up for Medicare

Medicare enrollment depends on your age, disability status, current benefits, and employer coverage. Start by identifying the enrollment period that applies before choosing Part A, Part B, or both.

Start with your enrollment status

Some people are enrolled automatically. Others must apply through Social Security. Do not assume that Medicare Open Enrollment is the period for first signing up for Part A or Part B.

Who handles enrollment

The Social Security Administration processes most applications for Medicare Part A and Part B. The Railroad Retirement Board handles enrollment for many railroad workers and beneficiaries.

Main enrollment periods

  • Initial Enrollment Period: usually a seven-month period beginning three months before the month you turn 65 and ending three months after that month.
  • Special Enrollment Period: may apply when you delayed Part B because you or your spouse had group health coverage based on current employment.
  • General Enrollment Period: January 1 through March 31 each year when another enrollment period does not apply. Coverage generally starts the month after enrollment, and a late penalty may apply.

Before you apply

Check whether you are already receiving Social Security or Railroad Retirement benefits, whether you have active employer group coverage, and whether you need Part A, Part B, or both. COBRA and retiree coverage do not always protect you from Part B late-enrollment consequences.

Help with Medicare costs

If premiums or other Medicare costs are difficult to pay, a Medicare Savings Program may help. Apply through the state Medicaid agency; Medicare and Social Security do not make the state eligibility decision.

Higher-income premiums and life changes

Social Security may add an income-related monthly adjustment amount (IRMAA) to Part B, Part D, or both based on IRS tax information. This is separate from Medicare enrollment and from a Medicare Savings Program. If a listed life-changing event reduces your income, you may ask Social Security to use more recent information with the current SSA-44.

Request a lower Medicare IRMAA after a life-changing event.

Enrollment and coverage appeals are separate tasks. If a Part D plan denies a drug, exception, utilization-management request, or payment, obtain the plan's formal coverage determination and use the appeal instructions in that notice. A level 1 Part D appeal is a redetermination by the plan.

If a Medicare drug plan denies coverage

Official starting points

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