Second-line treatment with paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) may achieve remissions in patients suffering from ovarian cancer who have failed primary chemotherapy with cisplatin- or carboplatin-based regimens. Introduction of paclitaxel in combination with cisplatin into the first-line treatment strategy was therefore the next logical step in the development of chemotherapy against ovarian cancer. Data already have shown that this may result in better survival. Since carboplatin may replace cisplatin, the combination of paclitaxel with carboplatin seemed a further necessary step. We therefore embarked on a dose-finding study of paclitaxel and carboplatin. Fourteen patients with International Federal of Gynecology and Obstetrics stage III and IV ovarian cancer with a median age of 55.5 years entered this study of escalating doses of either carboplatin or paclitaxel. Doses of carboplatin could be escalated from 300 to 450 mg/m2 and paclitaxel could be escalated from 125 to 175 mg/m2 without dose-limiting myelosuppression. At the highest dose level reported here, only transient short-lived leukopenia was observed. Other toxicities consisted of nausea and vomiting, peripheral neurotoxicity, and arthralgia, all mild. In the first 14 patients, 10 of whom are evaluable, complete remissions were seen in two patients and partial remissions in six. This study will escalate the doses of paclitaxel and carboplatin further. This treatment is well tolerated and yields satisfactory antitumor results.