Dogs were given no ethanol, 1.28 g ethanol/kg and 1.92 g ethanol/kg daily for 4 weeks immediately after castration. Plasma LH concentrations, basal and in response to 100 micrograms GnRH, were measured before and at 2 and 4 weeks after castration. Basal LH levels after castration increased significantly (P less than 0.005) within each group but were not significantly different between groups. GnRH-stimulated LH responses were similar before and at 23 weeks after castration, but at 4 weeks the dogs given 1.92 g ethanol/kg had a significantly (P less than 0.05) greater response than did the control dogs. It is concluded that daily ethanol ingestion in the amounts employed in this study does not impair hypothalamic--pituitary function in male dogs.