The importance of estrogens for cardiovascular physiology in women is accepted, even if the clinical place for hormonal supplementation after menopause remains uncertain. However, although men produce significant quantities of estrogen, relatively little is known about the role of estrogens in the male cardiovascular system. Recent evidence about the epidemiology of cardiovascular disease, the mechanisms of action of estrogens, the biological actions of endogenously produced estrogens in men, and the acute and chronic effects of estrogens on the vasculature in both men and women, suggests that these hormones may well play an important role in normal male cardiovascular physiology. In addition, they may provide useful adjuncts to therapy in selected groups of men.