A noticeable masculinizing effect with a high level of testosterone (T) in the blood up to its level in healthy males was obtained during treatment of 10 patients with primary (hypergonadotropic) hypogonadism using sustanon-250 at a dose of 1 ml i. m. once in 3-4 weeks. However no decrease in the initially elevated levels of the follicle-stimulating and luteinizing hormones was observed. The treatment of 21 patients with hypogonadotropic hypogonadism by small doses of chorionic gonadotropin (CG) (up to 1500 Units i. m. 3 times a weeks) turned out ineffective. The use of high doses of CG (3000-4000 units i. m. 3 times a week) or CG combined with menopause gonadotropin in most patients of this group produced a short-term clinical effect with an elevated T level in the blood. Hypogonadotropic hypogonadism combined with an acute decrease in the response of the testes to CG treatment even at large doses was found in 4 patients under 6 years with cryptorchidism who had undergone surgery for descent of the testes into the scrotum.