The major source of endogenous estrogens in postmenopausal women is the aromatization of androgens to estrogens; because alcohol is known to increase aromatization, the relationship between moderate alcoholic beverage consumption and serum estradiol levels was evaluated in 128 normal postmenopausal women. Alcohol intake was based on a composite of self-report and food record information. Among the 78.8% of women reporting alcohol use, weekly intake was 4.8 +/- 0.6 drinks. Among abstainers, estradiol levels were 100.8 +/- 12.1 pmol/liter, significantly lower than in alcohol users, 162.6 +/- 11.9 pmol/liter. Significant bivariate correlations were found between the logarithm of estradiol and total weekly drinks. In multiple linear regression analyses inclusion of alcohol as a variable increased the amount of explained variation in estradiol. Similar findings were demonstrable when the crude estimator of aromatization, the estradiol:testosterone ratio logarithm was the dependent variable. Together, these findings suggest that moderate alcohol use is an important factor for postmenopausal estrogen status and may offer a partial explanation for the reported protective effect of moderate alcohol consumption with respect to postmenopausal cardiovascular disease risk.