Medicare covers a broad range of medical services for adults 65 and older, from hospital stays and doctor visits to preventive screenings, mental health care, and prescription drugs. The program is split into distinct parts, each handling different types of care, and understanding what falls under each part helps you avoid unexpected bills and take full advantage of benefits you’re already paying for.
Part A: Hospital and Inpatient Care
Part A is hospital insurance. It covers inpatient stays at hospitals and critical access hospitals, skilled nursing facility care after a qualifying hospital stay, hospice care, and some home health services. Most people don’t pay a monthly premium for Part A if they or a spouse paid Medicare taxes for at least 10 years.
Part A also covers inpatient psychiatric care in both general hospitals and stand-alone psychiatric facilities. If you need hospice care for a terminal illness, Part A pays for comfort-focused treatment including pain management, counseling, and short-term respite care for your caregiver.
Part B: Doctor Visits and Outpatient Services
Part B is medical insurance, covering two broad categories: medically necessary services and preventive care. On the medically necessary side, that includes doctor’s office visits, outpatient procedures, ambulance services, durable medical equipment (wheelchairs, walkers, oxygen equipment), mental health counseling, and a limited number of outpatient prescription drugs. In 2025, the standard Part B premium is $185.00 per month, with an annual deductible of $257.
After you meet that deductible, you typically pay 20% of the Medicare-approved amount for most services. That 20% coinsurance has no built-in cap under Original Medicare, which is one reason many seniors add supplemental coverage.
Preventive Services at No Cost
One of Part B’s most valuable features is its roster of preventive services available at zero cost to you, as long as your provider accepts Medicare assignment. The list is extensive:
- Cancer screenings: mammograms, colorectal cancer screenings (colonoscopies, stool DNA tests, fecal occult blood tests), cervical and vaginal cancer screenings, lung cancer screenings, and prostate cancer screenings
- Cardiovascular care: cardiovascular disease screenings, behavioral therapy for heart disease risk
- Diabetes: diabetes screenings, self-management training, the Medicare Diabetes Prevention Program, and medical nutrition therapy
- Vaccines: flu shots, COVID-19 vaccines, pneumococcal shots, and hepatitis B shots
- Other screenings: bone mass measurements, glaucoma tests, HIV screenings, hepatitis B and C screenings, depression screenings, sexually transmitted infection screenings, and abdominal aortic aneurysm screenings
- Counseling: alcohol misuse counseling, tobacco cessation counseling, obesity behavioral therapy
You also get a one-time “Welcome to Medicare” preventive visit when you first enroll, plus a yearly wellness visit every year after that. These visits are designed to create or update a personalized prevention plan, not to address acute health problems.
Mental Health and Substance Use Coverage
Medicare covers mental health care on both the inpatient and outpatient side. Part A pays for psychiatric hospitalizations, while Part B covers outpatient counseling, psychotherapy, and services at community mental health centers. For people who need more intensive support without full hospitalization, Part B covers partial hospitalization programs (at least 20 hours of services per week) and intensive outpatient programs (at least 9 hours per week).
Substance use disorder treatment follows a similar structure. Outpatient counseling, therapy, and assessments for opioid use disorder and other conditions are covered under Part B. Prescription medications for mental health conditions typically fall under Part D drug coverage.
Part D: Prescription Drug Coverage
Part D covers outpatient prescription drugs through private insurance plans that contract with Medicare. You can get Part D as a stand-alone plan paired with Original Medicare, or it may be bundled into a Medicare Advantage plan. Each Part D plan has its own formulary (list of covered drugs), premiums, and cost-sharing tiers.
A major recent change: starting in 2025, Part D plans include a $2,000 annual cap on out-of-pocket prescription drug spending. Once you hit that threshold, you pay nothing more for covered drugs for the rest of the year. This is a significant shift for seniors who take expensive medications, particularly for conditions like cancer, rheumatoid arthritis, or multiple sclerosis, where a single drug could previously cost thousands out of pocket.
Medicare Advantage (Part C)
Medicare Advantage plans are an alternative way to receive your Medicare benefits. These are offered by private insurers approved by Medicare, and they must cover everything Original Medicare (Parts A and B) covers. The appeal is that many plans bundle in extras that Original Medicare does not provide, including dental care, vision coverage, hearing aids, and fitness or wellness programs. Most Medicare Advantage plans also include Part D drug coverage.
The trade-off is that Advantage plans typically use provider networks. You may need to use in-network doctors and hospitals, and you’ll often need referrals to see specialists. However, unlike Original Medicare, Advantage plans are required to set an annual out-of-pocket maximum, which protects you from unlimited cost-sharing.
Home Health Services
Medicare covers skilled nursing care and physical, occupational, or speech therapy delivered in your home, but only if you meet specific criteria. You must be considered “homebound,” meaning leaving your home is a major effort due to illness or injury, requires assistive devices like a wheelchair or walker, or isn’t recommended because of your condition. You also need to require part-time or intermittent skilled care, not just help with daily activities like bathing or cooking.
When you qualify, Medicare covers the skilled services at no cost to you. This can include wound care, injections, physical therapy after a fall or surgery, and monitoring of a serious or unstable health condition. A doctor must certify that you need these services and establish a care plan.
What Medicare Does Not Cover
Original Medicare has some notable gaps. It does not cover long-term custodial care, which is the kind of ongoing help with daily living (dressing, bathing, eating) that many seniors eventually need in a nursing home or assisted living facility. It also excludes most dental care: routine cleanings, fillings, tooth extractions, and dentures are not covered. Eye exams for prescription glasses are excluded as well, along with the glasses themselves.
Hearing aids are not covered under Original Medicare, though hearing exams to diagnose a medical condition are. Routine foot care, cosmetic surgery, and care received outside the United States are also generally excluded. These gaps are a primary reason many seniors turn to Medicare Advantage plans (which often include dental, vision, and hearing) or purchase supplemental coverage.
Filling the Gaps With Medigap
Medigap (Medicare Supplement Insurance) policies are sold by private insurers to help cover costs that Original Medicare leaves behind, like coinsurance, copayments, and deductibles. There are 10 standardized plan types, labeled A through N, each offering a different level of coverage.
All Medigap plans cover Part A coinsurance and hospital costs for up to an additional 365 days after your regular Medicare benefits run out. Most plans also cover 100% of Part B coinsurance, though Plans K and L cover only 50% and 75%, respectively, until you hit their annual out-of-pocket limits. Plan N covers Part B coinsurance but may require small copayments for certain office and emergency room visits.
Medigap does not cover prescription drugs, dental, vision, hearing aids, or long-term care. It works only with Original Medicare, not with Medicare Advantage. If you want Medigap, the best time to buy is during your six-month open enrollment window that starts the month you turn 65 and are enrolled in Part B. During that window, insurers cannot deny you coverage or charge more based on health conditions.