Although lifetime exposure to potentially traumatic events among older adults is fairly high, rates of full-blown post-traumatic stress disorder (PTSD) are estimated at about 4.5%, a rate lower than that for middle-aged and young adults. Nevertheless, PTSD seems to be an under-recognized and under-treated condition in older adults. Assessment and treatment can be challenging in this population for various reasons, including potential cognitive or sensory decline and comorbid mental and physical disorders. This article provides highlights of the empirical research on PTSD in late life, including information on its effects on cognition and physical health. The bulk of this piece is spent on reviewing the theory, description of, and efficacy for an evidence-based psychotherapy, Prolonged Exposure (PE), for PTSD. A detailed successful application of PE with an older veteran with severe, chronic PTSD in the Department of Veterans Affairs Health Care System is presented. Evidence-based psychotherapy for PTSD can be safely and effectively used with older individuals.