Forty-two patients affected by either stage III and IV ovarian cancer with residual tumor after surgery or recurrent ovarian cancer entered a phase II study of the combination carboplatin 300 mg/m2 and cyclophosphamide 600 mg/m2 every 28 days. Thirty-eight patients were evaluable for response and of these 27 obtained complete or partial remission with a 71% overall remission (clinical complete remission 45%; partial remission 26%). Treatment tolerability was on the whole good. The most frequent side effects were leukopenia (76%), anemia (67%) and nausea/vomiting (60%). Thrombocytopenia was present in 31% of the patients, but nearly always to a mild degree except for one grade 4 case. No other grade 4 side effect was observed. We did not observe any cases of nephrotoxicity and only two patients complained of paresthesia. This carboplatin-cyclophosphamide combination in advanced ovarian carcinoma produces comparable results, in terms of objective responses, to those obtained with standard cisplatin-based regimens, with suggestion of a better toxicological profile.