The gonadal functions were studied in 54 patients with disseminated nonseminomatous testicular tumors who had been subjected to combination chemotherapy (cisplatin, vinblastine, and bleomycin [PVB]) and surgery (hemiorchiectomy, retroperitoneal lymph node dissection or removal of retroperitoneal residual tumor after chemotherapy) and in 17 patients with a stage I tumor subjected to hemiorchiectomy exclusively. In the patients treated with chemotherapy, the plasma testosterone levels remained at the lower limit of normal and the luteinizing hormone (LH) levels remained elevated for 2 years after completion of treatment. The follicle-stimulating hormone (FSH) levels also remained significantly elevated, but showed a tendency to decrease after 2 years. Semen analysis was performed in 25 patients; of the other patients, 18 had no antegrade ejaculation, eight had undergone a vasectomy and three patients did not cooperate. Before treatment, 72% of the patients showed azoo- or oligozoospermia; 2 years after discontinuation of the chemotherapy, 48% had azoo- or oligozoospermia while 28% had more than 60 X 10(6) spermatozoa/mL. However, interestingly the proportion of patients with azoospermia had increased from 4% to 28%. In the course of this study, eight pregnancies occurred; one ended in an early spontaneous abortion; the other seven pregnancies ran an uncomplicated course. Seven healthy children were born. In 17 patients with a stage I tumor treated by hemiorchiectomy only, the testosterone, LH and FSH levels were also observed for 2 years; until 2 years after treatment, the testosterone levels remained lower and the FSH levels remained higher than normal. Insufficiency of the Leydig's cells in the unaffected gonad appeared to be responsible for the altered hormone concentrations in the blood.