OBJECTIVE This study was performed to determine the effectiveness of postoperative adjuvant chemotherapy in patients with surgically resected ovarian germ cell tumors. METHODS After tumor removal and thorough surgical staging, patients were enrolled on this study and treated with three courses of cisplatin, etoposide, and bleomycin (BEP). Reassessment laparotomy was required of consenting, appropriate patients initially, but became an optional procedure in 1989. RESULTS Of 93 patients assessable on this trial, 89 are continuously free of germ cell cancer. At second-look laparotomy, two other patients were found to have small foci of immature teratoma; both remain clinically free of recurrence. One received subsequent alternate chemotherapy and one did not. Thus, 91 of 93 patients are currently free of germ cell cancer. Follow-up duration ranges from 4.0 to 90.3 months, with 67 patients monitored for longer than 2 years. Acute toxicity was moderate. One patient developed acute myelomonocytic leukemia 22 months after diagnosis. Another patient was noted to have a malignant lymphoma 69 months after protocol treatment. CONCLUSIONS Three courses of BEP will nearly always prevent recurrence in well-staged patients with completely resected ovarian germ cell tumors and should be given to all such patients. The development of acute leukemia as a complication of treatment is disturbing and mandates careful long-term follow-up, but is unusual and does not alter the risk-to-benefit ratio of treatment.