Sixty-eight patients with relapsing, epithelial type ovarian carcinoma were entered into a Phase II study of vinblastine. Vinblastine was administered as a continuous intravenous infusion over five days at a starting dose of 1.7 mg/m2/day every 3 weeks. There were 44 fully evaluable and 6 partially evaluable patients. Forty-one of these patients had had only one prior treatment regimen. Grade 3 or 4 leukopenia occurred in 12 patients (24%), but Grade 3 or 4 thrombocytopenia occurred in only 2 patients. There were two clinical complete responses of 18 and 36 weeks duration and one partial response of 6 weeks for an overall response rate of 7%. We conclude that vinblastine, administered in optimal dose and schedule, has little clinical activity in previously treated patients with ovarian cancer.