Our study examines the national prevalence of cost-related nonadherence (CRN, e.g., skipping or reducing doses) among community-dwelling Medicare beneficiaries, separately for those over and under 65 years. We explore the relationship between CRN and major demographic and health-related characteristics. Additionally, we examine the extent to which beneficiaries report using drug cost reduction strategies (such as requesting generics) and spending less on other necessities (heat, food) to afford medicines. The analyses draw upon data from the 2016 Medicare Current Beneficiary Survey (MCBS), an annual federal survey of approximately 15,000 Medicare beneficiaries conducted by the Centers for Medicare and Medicaid Services (CMS). Approximately 14% of older enrollees and 34% of younger enrollees (having permanent disability status) reported not taking their medications as prescribed due to the costs of medication. Logistic regression analyses highlight the greater odds of CRN among particularly vulnerable population groups. For example, among the over-65 population, even when controlling for other factors such as education, sex, race, and ethnicity, individuals with incomes between $15K and $25K per year had odds of CRN 50% higher than those with incomes >$50K, and those with 4+ chronic conditions faced odds twice as high as those with one or zero conditions. Skimping on medications, or not filling prescriptions at all, can have serious negative effects on subsequent health outcomes. Medicare offers subsidized drug coverage options, but policy improvements to better ensure access to needed medications is clearly merited.