This chapter explores the health of individual older people and how they behave when they feel ill. Throughout history, humans have sought many means of improving their health and delaying death, but just as modern biomedicine has begun to gain the upper hand on a broad range of communicable diseases, most the world’s national populations are aging and in need of a different sort of health care intervention, one for older people with chronic diseases and disabilities that is just beginning to be made a priority around the world. The health status of an older person is influenced by many social and behavioral factors, including lifelong health habits (such as diet and exercise), genetics, exposure to occupational and environmental hazards, and psychological stress. The quality and availability of health care throughout life also play a role in health in later life, though not as much as most of us might think.