This multicenter phase 2 trial was conducted by the Gynecologic Oncology Group to evaluate the activity and the safety of irofulven in patients with recurrent epithelial ovarian cancer. Eligible patients had documented recurrent ovarian cancer 6 to 12 months after receiving a front-line platinum-based regimen and no other chemotherapy. Patients were required to have measurable disease, performance status of 0 to 2, and adequate bone marrow, hepatic, and renal functions before study entry. The dose of irofulven was 0.45 mg/kg intravenously on days 1 and 8 every 21 days. Responses were defined by Response Evaluation Criteria in Solid Tumors. Fifty-five of 61 enrolled patients were evaluable for response and toxicity. There were 7 partial responses (12.7%), and 30 patients (54.6%) had stable disease. Median progression-free and overall survival were 6.4 months (1.3-37.5 months) and 22.1 months or more (2.8-57.8+ months), respectively. Patients received a median of 3 cycles (range, 1-21) of protocol therapy. Grade 4 hematologic toxicity was limited to reversible neutropenia and thrombocytopenia. Grade 4 nonhematologic toxicity was limited to one patient with anorexia and another with hypomagnesemia. Irofulven administered at this dose and schedule was well tolerated but had modest activity as a single agent.