ABSTRACT: The benefits of regular exercise are well recognized: improved cardiopulmonary and bone health; increased muscle tone, strength, and endurance; improved self-image and mood; and prevention of diseases, such as diabetes mellitus and hypertension. Numerous government and professional organizations have published recommendations to guide individuals regarding the frequency and intensity of physical activity required for maintenance of good health. Most guidelines are consistent in recommending that all healthy adults should aim to include a minimum of 150 minutes of moderate-intensity aerobic exercise, spread out across the week, to maintain cardiovascular health. In addition, activities that maintain or increase muscular strength and endurance and maintain flexibility and balance also should be performed at least twice per week. Most sedentary women of all ages can safely maintain a physically active lifestyle, provided they have no contraindications to exercise. However, it is recommended that women interested in participating in an organized exercise program undergo pre-exercise health screening and risk stratification to optimize safety and to develop an effective exercise prescription. Common sense strategies also should be implemented for exercise safety and injury prevention. The female reproductive system is highly sensitive to physiologic stress. Consequently, a vigorous training program is associated with a unique set of potential risks for the female exerciser, ranging from minor menstrual changes to amenorrhea. The physician needs to be aware of these occurrences and evaluate them to ensure that no other pathology is present. Pregnancy is a unique opportunity for physical activity because the benefits of a healthy lifestyle may have both short- and long-term implications for a pregnant woman and her offspring. In the absence of obstetric complications, physical activity is safe and desirable in pregnancy. The information compiled in this monograph serves as a scientific background and resource for practical recommendations regarding exercise prescription for the practicing obstetrician–gynecologist and primary care physician.