Anyone age 65 or over is eligible for Medicare. Most people age 65 and over are covered under Medicare Part A for free, based on their work records or on their spouse's work records. People over 65 who are not eligible for free Medicare Part A coverage can enroll in it and pay a monthly fee for the same coverage. However, this rate increases by 10% for each year after your 65th birthday that you wait to enroll. The rules of eligibility for Part B medical insurance are simpler than for Part A: If you are age 65 or over and are either a U.S. citizen or a permanent resident who has been here lawfully for five consecutive years, you are eligible to enroll in Medicare Part B medical insurance. This is true whether or not you are eligible for Part A hospital insurance.