Affordability is a cornerstone of any efficient and effective health care system. Discussions of healthcare affordability often center on the premiums – the upfront monthly cost of purchasing insurance. But equally important are the back-end deductibles, copays and coinsurance associated with actually accessing services. Cost sharing is especially important for adults age 65 and older, who are much more likely to live with one or more chronic conditions and face a higher financial burden to obtain necessary care. The Medicaid and Medicare programs include cost sharing protections for low-income beneficiaries, but important gaps, especially in Medicare, leave some low-income older adults exposed to sizeable, potentially even devastating, out-of-pocket costs. This brief explores and explains the Medicaid and Medicare cost sharing protections for low-income older adults, identifies the key shortcomings and gives recommendations to inform future advocacy.