Because of the beneficial effect of estrogens on the risk of cardiovascular disease and osteoporosis in postmenopausal women, the factors which influence endogenous postmenopausal estrogen levels are of substantial importance. The major source of postmenopausal estrogen is the aromatization of androgens to estrogens. Because alcohol is reported to increase aromatization rates, the relationship between serum estradiol and moderate alcohol consumption was examined in a group of 128 healthy Pittsburgh postmenopausal women, and a significant direct association was found. In order to address the generalizability of this finding, 3 comparable study populations of healthy postmenopausal women were recruited: 62 in Copenhagen, 34 in Lisbon and 20 in Madrid. Although no association was detected in the Madrid study sample, in both the Copenhagen and Lisbon study populations, not only were estradiol levels significantly increased in alcohol users as compared to abstainers, but also estradiol levels were significantly correlated with total weekly drinks consumed. Based on these findings in study samples of healthy postmenopausal women from Pittsburgh, Copenhagen and Lisbon, we conclude that the increase in estradiol levels seen with moderate alcoholic beverage consumption is not an isolated finding and speculate that moderate alcohol consumption by healthy postmenopausal women may have beneficial effects.