An hCG-like material has been extracted from human sperm. These experiments were designed to characterize this material. Sperms of 10 volunteers were separated from seminal fluid, washed in PBS three times, and resuspended in 0.5 ml of the same buffer. Samples were pooled; cells were disrupted by sonication and extracted in alkaline buffer by constant agitation at 4 degrees C. The extract was ultracentrifuged at 4 degrees C. Supernate was lyophilized and reconstituted in 2 cc of distilled water. This material presented a dose-response curve parallel to those of IS2-hCG and CR119 in beta hCG RIA. When chromatographed in a Sephadex G-150 column the extract eluted within the hCG range and immunoreacted in the specific beta hCG RIA. When absorbed onto a concanavalin A--Sepharose column, all recovered immunoreactive material eluted after exposure to alpha-D-methylglucoside, indicating that it is a glycoprotein. The extract stimulated progesterone and testosterone secretion in porcine granulosa cells and decapsulated rat testis, respectively, indicating its biologic potency.