The most common metabolic bone disorder is osteoporosis, which affects 25 million Americans, of whom 80% are women. Bone loss in women occurs most commonly after menopause, when the rate of loss may be as high as 2% per year. Bone mass can be determined with dual-energy x-ray absorptiometry. The rate of active loss can be assayed by the detection of bone collagen breakdown products (e.g., N-telopeptide, pyridinoline) in the urine. Although it has been suggested that white women are most commonly affected, Hispanic and Asian women are also affected. Strategies for the prevention and treatment of osteoporosis are directed at maximizing peak bone mass by optimizing physiologic intake of calcium, vitamin D therapy, exercise, and maintenance of normal menstrual cycles from youth through adulthood. Coupled with drug therapy should be a comprehensive approach to exercise and fall prevention. Stretching, strengthening, impact, and balance exercises are effective. Of the balance exercises, tai chi chuan has proved to be the most successful in decreasing falls. Prevention of bone loss is obviously preferable to any remedial measures, but new therapeutic strategies provide a means of restoring deficient bone.