The incarcerated population is aging. Newly arrested individuals and those aging in prison from mandatory lengthy sentences contribute to this dynamic. Screening for impairment and developing effective interventions and treatment for the incarcerated elderly has become a substantial challenge. The number of U.S. prisoners aged 65 or older grew at 94 times the rate of the overall prison population between 2007-2012. In 2011 7.9% of state and federal inmates were 55 or older; there were 26,700 over age 65. The number of inmates over 60 years of age in U.K. prisons increased by 120% between 2002 and 2013. Similar growth trends are reported in Sweden, Japan, Australia and Canada. This growth is complicated by the fact that chronological age does not necessarily match ‘health age’ or health status in prison. As a result, many prison systems have adjusted their definition of ‘elderly’ down to age 55 (and some as low as 40) to reflect the relatively poor health status of aging men and women in their institutions. Typical correctional health services in prisons across the U.S. are already hard-pressed to keep up with increasing demands for care of aging inmates. The responsibility to provide adequate health services for prisoners remains despite shrinking local, county, state and federal budgets. This chapter reviews the current status and prevalence of the incarcerated elderly, and presents best practice models for their care.