Currently available data are of variable rigor and from a variety of sources, yet they do support several conclusions about the potential value of exercise for whole groups of elderly persons. (1) Exercise of moderate intensity may benefit many elderly persons in numerous and complementary ways (e.g., cardiovascular status, fracture risk, functional ability, and mental processing). (2) There are few complications associated with such increases in activity. Indeed, a remarkable aspect of research on exercise in the elderly has been the virtual absence of reports of serious cardiovascular or musculoskeletal complications in any published trials. Cardiac rehabilitation programs, enrolling many persons over 65 years of age with known coronary artery disease, also report few major cardiovascular complications. Thus, exercise should be viewed as safe for most older adults. (3) Exercise in the elderly probably needs to be tailored, and when possible, individualized, with the specific objectives of the person or group in mind. Some benefits are probably related to the intensity of exercise (e.g., cardiovascular disease), others due to the type of exercise (weight-bearing versus nonweight-bearing for osteoporosis, or racket sports for hand-eye coordination), and still others possibly relate to the setting in which exercise occurs (social-psychological benefits). (4) The authors believe the known physiologic effects of exercise on age-related changes and existing clinical research support the general notion that vigorous weight-bearing exercises such as walking are the safest, cheapest, easiest, and most widely beneficial for the average senior. (5) Research has yet to define good ways by which to stimulate large numbers of sedentary elderly persons to exercise regularly. The potential and complementary benefits appear to be great enough to justify widespread efforts at the community and individual level, however.