There has been no standard therapy for patients with metastatic colorectal cancer who have failed to first-line fluorouracil-based treatment. The present study was designed to assess the efficacy and toxicities of a combination of oxaliplatin, 5-fluorouracil (5-FU) and leucovorin in fluoropyrimidine-pretreated patients with metastatic colorectal cancer. Chemotherapy consisted of oxaliplatin 85 mg/m² on day 1, followed by leucovorin 20 mg/m² and 5-FU 1,200 mg/m² on days 1 and 2. Treatment courses were repeated every two weeks. Thirty-nine patients were enrolled in this study. All patients previously received fluoropyrimidine-based chemotherapy. Thirty-one patients were assessable for response and 33 for treatment toxicity. Six patients required dose reduction of 5-FU due to grade III/IV cytopenia. Nausea/vomiting and peripheral neuropathy were common non-hematologic toxicities. Overall response rate was 42.0% including 3 complete response and 10 partial response. The median response duration was 91 days (range, 28-224+). The median duration of progression-free survival was 132 days (range, 40-308). A combination of oxaliplatin, 5-FU, and leucovorin showed high response rate in fluoropyrimidine-pretreated patients with metastatic colorectal cancer, but the duration of response was relatively short. It may be worthwhile to explore its therapeutic potential in the first-line treatment setting.