Cardiovascular disease (CVD) is the leading cause of death in women, and after menopause the incidence increases rapidly. The premenopausal state and estrogen status, appear to be a prophylactic against the mortality risk from CVD. The protective effect is believed to be mediated by beneficial changes in cholesterol levels. Estrogen decreases low density lipoprotein cholesterol (LDL-C) and increases high density lipoprotein cholesterol (HDL-C). The other possible mechanism is the direct effect of estrogen on arterial intima. The type and route of estrogen used in hormone replacement therapy determines the positive and negative effect of estrogen on the cardiovascular system. Most studies show a 50% or greater reduction in CVD and related mortality with postmenopausal estrogen administration. Progestogen addition to hormone replacement, may attenuate the beneficial effects of estrogen on cholesterol. However if used in low doses progesteron may not exert this negative effect on the cardivascular system.