Levels of beta-human chorionic gonadotropin (beta-hCG) were detected in semen under basal conditions. No significant correlation to levels of luteinizing hormone (LH) in blood was found. The beta-hCG level did not increase within 3-7 days after a 5000 IU dose of hCG was injected intramuscularly. Human chorionic gonadotropin was detected in semen only after injection. beta-Human chorionic gonadotropin in the semen represents a degradation product of circulating LH.