The efficacy and toxicity of combination intravenous carboplatin (300 mg/m2) and cyclophosphamide (600 mg/m2) were evaluated in 70 newly diagnosed patients with advanced-stage epithelial ovarian cancer. Cycles were administered at 4-week intervals for a total of six cycles, and treatment was provided on an outpatient basis without prehydration or forced diuresis. During treatment, patients were assessed by physical, gynecologic, and radiologic examinations. Seventy patients with a median age of 58 years (range, 35 to 77 years) were entered into the study. Most patients had serious cystadenocarcinoma; 78% had stage III or IV disease and 91% had grade II or III histologic subtype. Optimal debulking surgery was performed in only 46% of patients. The overall response rate to carboplatin/cyclophosphamide combination chemotherapy was 81%, with 66% achieving a clinical complete response. The median survival for all patients was 19+ months. For patients who had undergone optimal debulking surgery, median survival was 26 months, compared with a median survival of 13+ months for those who had undergone suboptimal surgery. Treatment was well tolerated by most patients. Significant nausea and vomiting (World Health Organization grades 2 to 3) occurred in only 6% of 377 cycles of therapy. Myelosuppression was mild, with leukopenia (WBC count less than or equal to 2 x 10(9)/L) observed in only 11 of 295 cycles (4%) and thrombocytopenia (less than or equal to 100 x 10(9)/L) in 17 of 279 cycles (6%). Nadir levels generally occurred on day 21 of each cycle. Symptomatic anemia requiring transfusion occurred in 18 of 290 cycles (6%). Moderate alopecia, necessitating use of a hairpiece, occurred in six patients; no signs or symptoms of neurotoxicity, ototoxicity, or nephrotoxicity were observed in any patient. Renal function was normal on follow-up investigation, which was performed a median of 5 months after completion of treatment. This study demonstrates that carboplatin/cyclophosphamide combination chemotherapy is well tolerated in women with advanced-stage epithelial ovarian cancer, and produces overall response rates and median survival times similar to those obtained with cisplatin-containing regimens.