“Most persons aged 65 or older are automatically entitled to premium-free Part A because they or their spouse paid Medicare payroll taxes for at least 40 quarters (about 10 years) on earnings covered by either the Social Security or the Railroad Retirement systems. Persons under the age of 65 who receive cash disability benefits from Social Security or the Railroad Retirement systems for at least 24 months are also entitled to Part A. (Since there is a 5-month waiting period for cash payments, the Medicare waiting period is effectively 29 months.)23 The 24-month waiting period is waived for persons with amyotrophic lateral sclerosis (ALS, or Lou Gehrig’s disease). Individuals of any age with ESRD [End-Stage Renal Disease] who receive dialysis on a regular basis or a kidney transplant are generally eligible for Medicare. Medicare coverage for individuals with ESRD usually starts the first day of the fourth month of dialysis treatments. In addition, individuals with one or more specified lung diseases or types of cancer who lived for six months during a certain period prior to diagnosis in an area subject to a public health emergency declaration by the Environmental Protection Agency (EPA) as of June 17, 2009, are also deemed entitled to benefits under Part A and eligible to enroll in Part B.
“Persons over the age of 65 who are not entitled to premium-free Part A may obtain coverage by paying a monthly premium ($458 in 2020) or, for persons with at least 30 quarters of covered employment, a reduced monthly premium ($252 in 2020).24 In addition, disabled persons who lose their cash benefits solely because of higher earnings, and subsequently lose their extended Medicare coverage, may continue their Medicare Part A enrollment by paying a premium, subject to limitations.”
Source: Patricia A. Davis, et al. Medicare Primer. CRS Report R40425. Congressional Research Service: Washington, DC. Updated May 21, 2020.
“Generally, enrollment in Medicare Part B is voluntary. All persons entitled to Part A (and persons over the age of 65 who are not entitled to premium-free Part A) may enroll in Part B by paying a monthly premium.25 In 2020, the monthly premium is $144.60; however, about 3% of Part B enrollees pay less, due to a “hold-harmless” provision in the Social Security Act.26 Since 2007, higher-income Part B enrollees pay higher premiums. (See “Part B Financing.”) Although enrollment in Part B is voluntary for most individuals, in most cases, those who enroll in Part A by paying a premium also must enroll in Part B. Additionally, ESRD beneficiaries and Medicare Advantage enrollees (discussed below) also must enroll in Part B.
“Together, Parts A and B of Medicare comprise original Medicare, which covers benefits on a fee-for-service basis. Beneficiaries have another option for coverage through private plans, called the Medicare Advantage (MA or Part C) program. When beneficiaries first become eligible for Medicare, they may choose either original Medicare or they may enroll in a private MA plan. Each fall, there is an annual open enrollment period during which time Medicare beneficiaries may choose a different MA plan, or leave or join the MA program.27 Beneficiaries are to receive information about their options to help them make informed decisions.28 In 2020, the annual open enrollment period runs from October 15 to December 7 for plan choices starting the following January. Since 2012, MA plans with a 5-star quality rating have been allowed to enroll Medicare beneficiaries who are either in traditional Medicare or in an MA plan with a lower quality rating at any time.
“Finally, each individual enrolled in either Part A or Part B is also entitled to obtain qualified prescription drug coverage through enrollment in a Part D prescription drug plan. Similar to Part B, enrollment in Part D is voluntary and the beneficiary pays a monthly premium. Since 2011, some higher-income enrollees pay higher premiums, similar to enrollees in Part B. Generally, beneficiaries enrolled in an MA plan providing qualified prescription drug coverage (MA-PD plan) must obtain their prescription drug coverage through that plan.29“
Source: Patricia A. Davis, et al. Medicare Primer. CRS Report R40425. Congressional Research Service: Washington, DC. Updated May 21, 2020.
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Page last updated March 17, 2025 by Doug McVay, Editor.