This self-directed learning module highlights the diagnosis and rehabilitation management of acquired disabling disorders. It is part of the chapter on geriatric rehabilitation in the Self-Directed Medical Knowledge Program for practitioners and trainees in physical medicine and rehabilitation. This article contains information on the physiology of aging; rehabilitation management of pathologic conditions of the older adult affecting the cardiovascular, pulmonary, skeletal, connective tissue, and neurologic systems; rehabilitation issues relating to psychologic functioning of the older adult; pharmacologic concerns of the older adult; and response to illness with aging.