Coronary heart disease is the single leading cause of death in women and a significant cause of disability. Menopause adversely affects several risk factors for coronary heart disease, suggesting that hormones influence the risk of coronary heart disease in postmenopausal women. This article reviews the observational and clinical trial data evaluating the relation between cardiovascular disease and hormone replacement therapy. Biological mechanisms of estrogen and the impact of adding progestins are emphasized. Potential risks and benefits of therapy are discussed. The relative effects of other estrogen and lipid-lowering therapies for preventing coronary heart disease in postmenopausal women are highlighted.