Thirty-one ovarian cancer patients with minimal residual disease after intravenous cisplatin combination chemotherapy were treated with intraperitoneal carboplatin (IP-Ca). The dose of IP-Ca was escalated from 150 to 350 mg/m2. Twenty-two patients received at least three courses of IP-Ca and were evaluable for efficacy. Third-look laparotomy was done in 10 patients. Two patients obtained a complete pathological response (CPR) lasting 33+ and 41+ months, respectively; 8 patients had minimal residual disease. Median survival for all patients was 14+ months. All patients were eligible for toxicity. Maximum tolerable dose in these heavily pretreated patients was 300 mg/m2 IP-Ca. The dose-limiting toxicity was thrombocytopenia; in 27% of the patients who received 350 mg/m2 IP-Ca, WHO grade 4 thrombocytopenia was seen. No patient had WHO grade 4 leukopenia. Subjective side effects consisted of mild nausea and vomiting (WHO). In conclusion, IP-Ca can produce CPR in heavily pretreated patients with only minor side effects.