Osteoporosis is a common condition of older Americans, particularly older women. In addition to advanced age and female gender, risk factors for decreased bone mass include Caucasian race, thin frame, excessive alcohol intake, smoking, and sedentary lifestyle. At-risk patients require a careful history and physical examination aimed at ruling out secondary causes, including systemic disease and certain drugs. Routine lab tests are also recommended. To make a definitive diagnosis, bone loss must be documented with densitometry. The most precise technology available is dual energy x-ray absorptiometry, although several other methods also can be used.