Over a 7-year period, semen analysis was performed in 92 male patients with Hodgkin's disease prior to therapy. In 67% of patients semen revealed a decreased chance for fertility (i.e. oligozoospermia, asthenozoospermia and/or teratozoospermia). The mean basal levels of follicle-stimulating hormone (FSH), luteinising hormone, testosterone and prolactin were in the normal range. In 77 patients in complete remission after alternating MOPP/ABVD (mechlorethamine, vincristine, procarbazine, prednisone; doxorubicin, bleomycin, vinblastine, dacarbazine), testicular function was assessed. 87% of patients were azoospermic, 9% had semen abnormalities and only 4% were normospermic. Recovery of spermatogenesis was documented in only 17 of 42 (40%) reassessed patients after a median time of 27 months and was generally not affected by pretreatment sperm quality. After chemotherapy, the mean value of FSH [20.45 (S.E. 1.7) mUI/ml] was significantly superior compared with that of the mean pretreatment values. No difference was documented in the mean testosterone and prolactin values tested before and after treatment. Our findings indicate that, of patients with Hodgkin's disease, about half are affected by hypogonadism before starting chemotherapy. By utilising alternating MOPP/ABVD, persistent testicular dysfunction was documented in half of the patients.