Cyclophosphamide (CTX) 600 mg/m2, carboplatin 280 mg/m2, and cisplatin 50 mg/m2 were administered on day 1 every 4 weeks to 41 previously untreated ovarian cancer patients with residual disease greater than 2.0 cm after primary laparotomy. Of 22 patients with measurable disease treated with up to eight cycles of therapy, the overall clinical response rate was 73% (exact 95% confidence interval [CI], 50% to 89%), with 50% complete response (CR). Six of 11 clinical CR (cCR) patients underwent surgical restaging; three pathologic CRs (pCRs) and three pathologic partial responses (pPRs) with residual disease less than 2.0 cm were documented. Fourteen patients had nonmeasurable but assessable disease; the clinical response rate was 57% (Cl, 29% to 82%) with two (14%) CRs. Second-look surgery was performed in one of the two cCR patients; a pPR was documented. Five patients with nonassessable disease were stable during chemotherapy; two underwent surgery and had pCRs. The median time to treatment failure (TTF) was 14.8 months, and median survival for the 41 patients is 26.7 months. Overall, 37% of the patients had progression-free intervals of at least 2 years, and 27% have survival times in excess of 3 years. Hematologic toxicity was substantial but manageable, with 58% and 66% experiencing a granulocyte nadir less than 500/microL and a platelet nadir less than 50,000/microL, respectively. One treatment-associated fatality occurred as a result of leukopenic sepsis and renal failure in the setting of progressive disease and ureteral obstruction. Mild to moderate nausea and vomiting occurred in most patients, but none experienced severe ototoxicity or peripheral neuropathy. Over all courses, 73% of the projected dose intensity of CTX and carboplatin and 86% of cisplatin were delivered. Since granulocytopenia and thrombocytopenia were dose-limiting, the addition of colony-stimulating factors that support both myeloid and megakaryocyte precursors may permit further dose intensification.