There are many ways to qualify for Medicare. There are two parts of Medicare, each of which has its own requirements:

Hospital Insurance (also known as Part A)

Most people 65 or older are eligible for Medicare hospital insurance (Part A) based on their own—or their spouse's— employment. You are eligible at 65 if you: 

• receive Social Security or railroad retirement benefits;
• are not getting Social Security or railroad retirement benefits, but you have worked long enough to be eligible for them;
• would be entitled to Social Security benefits based on your spouse's (or divorced spouse's) work record, and that spouse is at least 62 (your spouse does not have to apply for benefits in order for you to be eligible based on your spouse's work) ;or 
• worked long enough in a federal, state, or local government job to be insured for Medicare. 

Before age 65, you are eligible for Medicare hospital insurance if you:

• get Social Security disability benefits and have amyotrophic lateral sclerosis (Lou Gehrig's) disease; or
• have been a Social Security disability beneficiary for 24 months; or
• have worked long enough in a federal, state, or local government job and you meet the requirements of the Social Security disability program.

If you receive a disability annuity from the Railroad Retirement Board, you will be eligible for hospital insurance after a waiting period. (Contact your railroad retirement office for details.) 

Under certain conditions, your spouse, divorced spouse, widow or widower, or a dependent parent may be eligible for hospital insurance when he or she turns 65, based on your work record.

Also, disabled widows and widowers under age 65, disabled divorced widows and widowers under 65, and disabled children may be eligible for Medicare, usually after a 24-month qualifying period. (For disabled widows/widowers, previous months of eligibility for Supplemental Security Income (SSI) based on disability may count toward the qualifying period.) 

There are special rules for people with permanent kidney failure. Under these rules, you are eligible for hospital insurance at any age if you receive maintenance dialysis or a kidney transplant and: 

• you are insured or are getting monthly benefits under Social Security or the railroad retirement system; or
• you have worked long enough in government to be insured for Medicare.

In addition, your spouse or child may be eligible, based on your work record, if she or he receives continuing dialysis for permanent kidney failure or had a kidney transplant, even if no one else in the family is getting Medicare. 

Certain aged people who do not qualify for Medicare hospital insurance under these rules may be able to get it by paying a monthly premium. They must also always enroll in medical insurance (Part B) to get this coverage. Certain disabled people who lost premium-free hospital insurance due to work can get Medicare hospital insurance again by paying a premium.

Almost anyone who is 65 or older or who is under 65 but eligible for hospital insurance can enroll for Medicare medical insurance by paying a monthly premium. Aged people don't need any Social Security or government work credits for this part of Medicare.