OBJECTIVE To evaluate the effects of chronic alcoholism on the male fertility hormones and quality of semen. METHODS Non-probability purposive clinical study. METHODS Addiction treatment center and an academic research environment. METHODS Sixty-six alcoholics free from smoking and drug abuse who consumed a minimum of 180 mL of alcohol per day (brandy and whisky, both 40%-50% alcohol content) for a minimum of 5 days per week for > or =1 year were included. Thirty nonsmoking nonalcoholics were selected as controls. METHODS Before starting the addiction treatment for alcoholics, venous blood and semen samples were collected. METHODS Complete blood counts, biochemical parameters, levels of the male fertility hormones FSH, LH, T, PRL, P, and E2 in blood, and semen parameters. RESULTS In alcoholics, FSH, LH, and E2 levels were significantly increased, and T and P levels were significantly decreased. No significant change was noted in PRL levels. Semen volume, sperm count, motility, and number of morphologically normal sperm were significantly decreased. CONCLUSIONS Chronic alcohol consumption has a detrimental effect on male reproductive hormones and on semen quality.