Almost all people over age 65 are automatically eligible for hospital insurance (Part A), which covers inpatient hospital services, outpatient diagnostic services, and post-hospital care in the patient's home or in an extended family. Medical insurance (Part B), a voluntary plan to all people over 65 and certain disabled persons, covers most physician services wherever they are furnished, home health services, or services for End Stage Renal Disease (ESRD) and other medical and health services.

Each beneficiary will receive a health insurance card which will show whether he/she has hospital insurance (Part A) or medical insurance (Part B) or both, and the effective date(s) of his/her coverage. When a husband and wife are both covered, each will have a separate card.

The beneficiary's Medicare number (HIC number) shown on the card is usually their social security number followed by a one or two digit alpha or numeric suffix which helps to further identify the patient.