To evaluate the efficacy of intraperitoneal (IP) carboplatin-based therapy as salvage treatment of ovarian cancer, 46 patients with persistent or recurrent ovarian cancer following initial systemic chemotherapy were treated with a regimen of carboplatin (200-300 mg/m2) and etoposide (100 mg/m2) administered on a monthly schedule. A maximum of six courses of therapy was delivered, followed by a response laparotomy. The treatment program was well tolerated, except for bone marrow suppression, with one-quarter of patients developing platelet count depressions to < or = 50,000/mm3, and one-third experiencing hemoglobin levels of < or = 8 g/dl during treatment. Twelve (38%) of 32 patients evaluable for efficacy of the treatment program achieved a surgically documented response, including 8 (25%) complete responses. Of 25 patients whose largest tumor mass at the initiation of therapy measured < or = 0.5 cm, 11 (44%) responded, including 8 (32%) complete responses. We conclude that the IP administration of carboplatin can result in surgically documented responses when used in the salvage setting in patients with advanced ovarian cancer. The relative efficacy of carboplatin versus cisplatin when administered by the IP route to patients with ovarian cancer previously treated with platinum-based systemic therapy remains to be defined.