Testicular and ovarian functions were assessed in 33 patients with Hodgkin's disease 1 to 17 years after cessation of COPP chemotherapy with cyclophosphamide, vincristine, procarbazine, prednisone. Diagnostic procedures consisted of hormone measurements, interviews, and semen analyses. In women serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), 17β-estradiol, progesterone, prolactin, and in men FSH, LH, 17β-estradiol, testosterone, and prolactin were determined. Semen analyses were performed in all men. Information concerning pregnancies, pregnancy outcome, future fertility wishes, sexual functions, menstrual pattern, and incidence of premature menopausal symptoms was ascertained by interview and questionnaire. Nineteen of 19 (100%) men showed elevated serum FSH levels between 715 and 1910 (median 1095) ng/ml and azoospermia, 1 to 11 years afters therapy. Serum levels of testosterone were within normal limits in 18/19 (95%) of the men, and LH values were normal in all men. Permanent ovarian failure occurred in 8/14 (57%) women, causing infertility and premature menopausal symptoms. The incidence of ovarian failure in women over 24 years was 86% (6/7) versus 28% (2/7) in those under 24 years at the time of treatment. In women receiving estrogen replacement, incidence and severity of these symptoms were significantly reduced. Of 14 women 3(21%) became pregnant and delivered 5 healthy children after treatment. Our results suggest irreversible sterility and normal Leydig cell function after COPP chemotherapy in all men. Druginduced ovarian failure was age-related and caused premature menopausal symptoms, detracting from the quality of the patient's life. To reduce premature menopausal symptoms and to prevent adverse cardiovascular and metabolic late sequelae, hormonal replacement is indicated. Pregnancies ending in normal live births can be achieved after COPP chemotherapy in young women. In both men and women, serum FSH and LH levels proved to be feasible markers to determine degree and duration of endocrine and reproductive gonadal injury after chemotherapy.