This statement summarizes the U.S. Preventive Services Task Force (USPSTF) recommendations for use of hormone replacement therapy for the primary prevention of chronic conditions in postmenopausal women and updates the 1996 USPSTF recommendations on this topic. The complete information on which this statement is based, including evidence tables and references, is available through the USPSTF Web site (http://www.preventiveservices.ahrq.gov) and through the National Guideline Clearinghouse (http://www.guideline.gov) The USPSTF reviewed the evidence on the use of postmenopausal hormone replacement therapy and the following outcomes: cardiovascular disease, including CHD and stroke; osteoporosis and fractures; thromboembolism; dementia and cognitive function; breast, colon, ovarian, and endometrial cancer; and cholecystitis. The USPSTF also reviewed evidence of the effects of hormone replacement therapy on phytoestrogens and osteoporosis and cardiovascular disease. The use of hormone replacement therapy for relieving active symptoms of menopause, such as hot flashes, urogenital symptoms, and mood and sleep disturbances, among others, is outside the scope of these USPSTF recommendations, and literature on this topic was not reviewed. Sources for estimates of benefits and harms cited in this Recommendation statement are described in the summary of the evidence available from the Agency for Healthcare Research and Quality.