To evaluate the effect of ethanol on testicular function in chronic alcoholics without chronic liver disease, we studied 38 asymptomatic chronic alcoholics and 19 age-matched controls. Detailed clinical history, nutritional status, hormonal analysis, and seminal studies were conducted in each case and control. Alcoholic patients had an average of 39 +/- 2 years old (range: 26 to 60) and reported a daily ethanol consumption from 100 to 350 g (mean: 198 +/- 15) over a period of 18.0 +/- 1.2 years. Alcoholics exhibited a significant increase of the luteinizing hormone (p < 0.001) and a decrease of the Free Androgen Index, compared with controls (p < 0.05) that related significantly with the total lifetime dose of ethanol (p < 0.01, both). Seminal studies indicate that 39.4% of alcoholics had significantly reduced their spermatozoa count (p < 0.01), whereas significant morphological abnormalities were observed in 44.7% of the alcoholics (p < 0.01). Spermatozoa motility from alcoholics was also found to be altered in half of the patients (p < 0.01). A significant increase of serum luteinizing hormone, follicle-stimulating hormone, and sex hormone binding globulin levels, and a decrease of Free Androgen Index were observed in alcoholics with morphology and motility abnormalities (p < 0.05, all). In multivariate analysis, the only independent factor that determined the alterations in sperm (count, morphology abnormalities, and motility alterations) was the total lifetime of ethanol intake (p < 0.001, all). We conclude that alcoholics frequently develop a situation of primary hypogonadism related to a lifetime of ethanol consumption.