A total of 111 patients with advanced nonseminomatous testicular cancer underwent cisplatin-based combination chemotherapy, followed by surgical removal of residual masses in 101. Surgery included retroperitoneal lymph node dissection in 92 patients, thoracotomy in 19 and hepatic resection in 1 (11 patients underwent 2 operations). Complete necrosis and/or fibrosis was found in 52 operative specimens, mature teratoma in 37 and vital malignant tumor in 12. Of the 11 patients who underwent 2 operations 4 had complete necrosis and/or fibrosis in both histological specimens. After a median observation of 55 months 83 of 89 patients with complete necrosis and/or fibrosis or mature teratoma were without evidence of disease. Only 7 of 12 patients with vital malignant tumor in the operative specimen survived without evidence of disease. Relapses were observed in 16 patients, 4 of them in the retroperitoneal space. Of the 16 relapses 5 were in 12 patients with residual vital malignant tumor, 5 in 37 patients with post-chemotherapy mature teratoma and 4 in 52 patients with complete necrosis and/or fibrosis after chemotherapy. Two patients with recurrence did not undergo an operation. In patients in whom post-chemotherapy retroperitoneal lymph node dissection is considered complete necrosis and/or fibrosis can be predicted by the combination of several factors, including absence of teratomatous elements in the testicular tumor, complete response on post-chemotherapy computerized tomography, and normal alpha-fetoprotein and human chorionic gonadotropin levels after chemotherapy (sensitivity 83%, specificity 76% and correctly predicted 79%). With the knowledge of these factors it seems possible to omit post-chemotherapy retroperitoneal lymph node dissection in approximately 20% of the patients with advanced metastatic nonseminomatous testicular cancer with initial retroperitoneal tumors.