Medicare prescription drug coverage, officially called Part D, is available through two main options. First, you can enroll in a standalone Medicare Part D prescription drug plan that works alongside Original Medicare, some Medicare Cost Plans, Private Fee-for-Service plans, and Medical Savings Account plans. You must have Medicare Part A or Part B to join a separate Part D plan. Second, you can choose a Medicare Advantage Plan that includes prescription drug coverage, which provides all your Part A, Part B, and Part D benefits through one plan. Keep in mind that you need both Part A and Part B to join Medicare Advantage, and not all Medicare Advantage plans include drug coverage. To be eligible for any Medicare prescription drug plan, you must be a U.S. citizen or lawfully present in the United States. Compare specific costs and coverage details at Medicare.gov/plan-compare, and contact plans directly for additional information. For personalized help comparing plan costs and benefits, reach out to your State Health Insurance Assistance Program.