How do I enroll in Medicare? Answer: You'll be automatically enrolled in Medicare when you turn 65 if you're already receiving Social Security benefits, or when you apply for Social Security benefits at age 65. In either case, the Social Security Administration will notify you that you're being enrolled. Although there's no cost to enroll in Medicare Part A (Hospital Insurance), you'll pay a premium to enroll in Medicare Part B (Medical Insurance). If you've been automatically enrolled in Part B, you'll be notified that you have a certain amount of time after your enrollment date to decline coverage. Even if you decide not to enroll in Medicare Part B during the initial enrollment period, you can enroll later during the annual general enrollment period that runs from January 1 to March 31 each year. However, you may pay a slightly higher premium as a result. If you decide to postpone applying for Social Security past your 65th birthday, you can still enroll in Medicare when you turn 65 by visiting your local Social Security office. If you are unable to visit your local office, you may be able to enroll over the phone. To find your local office, check your telephone book or call the Social Security Administration at (800) 772-1213.