Alcoholism affects nine million individuals in the United States according to United States Government estimates. As many as 80% of hard-core alcoholic men show evidences of feminization including impotence, testicular atrophy, sterility, gynecomastia and changes in bodily hair. The causes of feminization of male alcoholics have remained obscure until recently. Largely as a result of advances in the techniques of measurement of sex hormones, it has become possible to begin to examine the pathogenesis of feminization. The results of initial studies suggest that alcoholics become feminized through the secondary effects of alcohol-induced liver disease, and also through primary effects of alcohol on the endocrine system. It can be shown that liver disease permits the peripheral escape of steroid precursors and their conversion to estrogenic substances. These substances are then inadequately cleared by the liver. In addition, however, alcohol alters testicular steroidogenesis and testosteronogenesis. Hypothalamic-pituitary function also is diminished in chronic alcoholics, and this change contributes to the syndrome of feminization.