Twenty-one patients with metastatic germ cell tumors achieved only partial clinical tumor regression following chemotherapy, and underwent surgical biopsy or resection of the residual tumor deposits. Sixteen (76%) are at present clinically disease-free after a median 30 + months (range 17-50 months) from the time of surgery, and five (24%) died after 9-29 months. Adverse prognostic signs were the finding of persistent cancer at histopathological examination of the resected tumor masses, and the presence of elevated serum tumor markers at the time of surgery. Postchemotherapy surgery in this setting provides tissue for the prognostically important histopathological examination on which a decision regarding further chemotherapy may be based. In addition, it provides tumor bulk reduction in the cases of differentiated teratoma and persistent cancer.