Medicare was first established in 1965. It is a federal health insurance program primarily designed for individuals aged 65 and older. It also covers younger individuals with disabilities and those suffering from specific medical conditions. These conditions specifically include end-stage renal disease (ESRD) and amyotrophic lateral sclerosis (ALS). The program is administered by the Centers for Medicare & Medicaid Services (CMS). This program consists of four major parts that have been discussed below comprehensively. Each program addresses specific healthcare needs and targets patients.