Medicare isn’t available to everyone, and you shouldn’t expect to be enrolled automatically. You are generally eligible to enroll in Medicare if:  You are 65 years or older; You are a United States citizen or a 5+ year permanent U.S. resident; You or your spouse worked and paid Medicare taxes for a minimum of 10 years. You may be eligible to enroll if you are under 65 due to end stage renal disease (ESRD), ALS or if you have been collecting social security disability insurance for 24 months. Once you are enrolled in Original Medicare (Parts A and B), you can then enroll in plans that offer additional benefits, such as a Medicare Advantage, Medicare Supplement Insurance or Medicare Part D plan.