Remission rates induced by chemotherapy alone or by combined chemotherapy and surgery were analyzed in relation to specific serum tumor marker abnormalities immediately before treatment in 103 patients with Stage I11 or bulky Stage I1 nonseminomatous germ cell tumors. Complete remission occurred in 92% (12 of 13) of patients with normal levels of alpha-fetoprotein (AFP) and human chorionic gonadotropin (HCC), in 26% (6/23) with elevated AFP only, in 46% (13/28) with elevated HCG only, and in 39% (13/36) with abnormalities of both AFP and HCC. Patients with elevated AFP less frequently had a complete remission (CR) to chemotherapy (CR, 34% versus 61% with normal AFP), but benefitted from adjunct surgery (CR, up to 59%). Patients with very high (>lo00 ng/ml) serum AFP or HCC responded poorly to chemotherapy (CR, 17%) but especially large tumor burdens may have contributed to these unfavorable responses. Patients with both minimal and advanced metastatic disease had higher CR rates if they had serum tumor marker levels below rather than above 1000 ng/ml. Adjunct surgery eliminated the correlation between the "poor prognostic factors" associated with specific marker abnormality and an incomplete response to chemotherapy by rendering a significant number of such patients free of disease through resection of residual metastatic deposits.