Medicare Card: How to Get, Replace and Use Yours
HSChange Editorial Team
Health Policy Research Team, Consumer Health Guidance
Reviewed by Dr. Sarah Mitchell, MD, MPH, Board-Certified Internal Medicine
Last updated: April 4, 2026
Your Medicare card is a red, white, and blue paper card that proves you have Medicare coverage. It shows your name, Medicare Beneficiary Identifier (MBI) number, and which parts of Medicare you're enrolled in (Part A, Part B, or both). You'll need it every time you see a doctor, go to the hospital, or fill a prescription under Part B.
When You Get Your Card
If you're automatically enrolled in Medicare (because you're already receiving Social Security), your card arrives in the mail about 3 months before you turn 65. If you sign up yourself through Social Security, the card comes after your enrollment is processed, usually within a few weeks.
The Medicare Beneficiary Identifier
Your MBI is an 11-character number that replaced the old Social Security-based Health Insurance Claim Number. The MBI uses a mix of numbers and uppercase letters (no S, L, O, I, B, or Z to avoid confusion). It doesn't contain your Social Security number, which protects against identity theft.
How to Replace a Lost Card
Log into your Medicare.gov account. Your MBI is displayed there immediately, so you can use it while waiting for a replacement card. You can also request a new card through your Medicare.gov account, by calling 1-800-MEDICARE (1-800-633-4227), or by visiting your local Social Security office. Replacement cards are free and arrive by mail within 30 days.
Medicare Card vs. Medicare Advantage Card
If you join a Medicare Advantage plan, you'll get a separate card from that insurer. Use the Medicare Advantage card for most care. But keep your original red, white, and blue Medicare card too. You need it if you leave Medicare Advantage and return to Original Medicare, and some providers ask for it even if you have MA coverage.
Protect Your Card
Don't share your MBI with anyone who contacts you unsolicited. Medicare will never call you to ask for your number. Scammers use fake Medicare calls to steal identities. Only give your MBI to doctors, pharmacies, insurers, and people you trust to file claims on your behalf.