One- half of women in the United States do not meet the weekly dose of physical activity recommended by the Centers for Disease Control. Many women could benefit tremendously if they were to adopt a more active lifestyle. Health benefits from exercise include lowering the risk for cardiovascular disease, slowing the rate of bone loss in osteoporosis, and improving mood during pregnancy. In this article, we review the health benefits that women may gain from physical activity and the recommendations for physical activity for adults in the United States. We offer evidence supporting use of the exercise prescription, discuss how to write an exercise prescription, and how to tailor the exercise prescription for women with particular medical problems.