Thirty-nine women with advanced, recurrent epithelial ovarian carcinoma who failed prior treatment with a platinum-based regimen were treated with leucovorin, 20 mg/m2 intravenously followed by 5-fluorouracil, 425 mg/m2 intravenously, daily for 5 consecutive days every 5 weeks in a phase II trial. Partial regressions were seen in 3 of 15 (20%) measurable disease patients, and objective regressions were seen in 3 of 14 (21%) evaluable/nonmeasurable disease patients. A 50% or greater decrease in CA-125 level was observed in 3 of 10 (30%) patients with no objectively evaluable or measurable disease. Overall objective response rate was 23% (95% confidence interval: 11 to 39%) in all 39 patients evaluated, with a median time to progression of 3 months and overall median survival of 7 months. Toxicities were acceptable and consisted of neutropenia, thrombocytopenia, stomatitis, and mild diarrhea. 5-Fluorouracil, as administered in this protocol, had modest antitumor activity in cisplatin-refractory ovarian carcinoma of short duration and minimal toxicity.