This statement summarizes the U.S. Preventive Services Task Force recommendations on hormone therapy for the prevention of chronic conditions in postmenopausal women and the supporting scientific evidence, and updates the Task Force's 2002 recommendations on hormone replacement therapy. The updated statement is based on the results of the Women's Health Initiative randomized, controlled trial, as well as the information in the 2002 summary of the evidence on this topic, which is available on the USPSTF Web site (http://www.preventiveservices.ahrq.gov).