Fertility and Leydig cell function were investigated in 31 patients previously treated for nonseminomatous testicular cancer. Twenty-two patients with metastatic cancer had received cisplatin-based chemotherapy, and the median follow-up was 64 months (range, 42 to 100 months). Nine patients without metastases were treated with orchiectomy alone, and follow-up in this group was a median of 61 months (range, 40 to 77 months). None of the patients have relapsed and retroperitoneal lymph node dissection was not performed in any patient. Both the concentration of spermatozoa and the volume of the remaining testis are significantly reduced in patients who had previously received chemotherapy when compared with patients treated with orchiectomy alone (P less than .05). There were no significant differences between groups when comparing morphology, motility, and penetration of the spermatozoa. Subclinical Leydig cell dysfunction with normal testosterone and elevated luteinizing hormone (LH) was observed in one patient (11%) treated with orchiectomy alone, while 59% of the patients who had received chemotherapy had elevated LH (P less than .05). We conclude that cisplatin-based chemotherapy leads to a persistent impairment of fertility and Leydig cell function in the majority of patients with testicular cancer.