Background: Many patients with extranodal natural killer/T-cell lymphoma (NTCL) fail to the front-line therapy and need an effective second-line chemotherapy. Patients and methods: This was single-institutional, phase II study. The primary end point was response rate and secondary end points were toxicity, time to treatment failure (TTF), and overall survival (OS). Patients with relapsed or refractory NTCL were eligible. They received the chemotherapy consisting of ifosfamide, methotrexate, etoposide, and prednisolone and it was repeated every 3 weeks. Results: Thirty-two patients were enrolled and 15 patients had achieved partial remission (PR) or complete remission (CR) after the front-line chemotherapy. The International Prognostic Index scores were 0–1 in thirteen, 2 in five, 3 in five, and 4–5 in nine patients. Twelve and two patients achieved CR and PR, respectively. Median OS and TTF of all patients were 8.2 and 3.7 months, respectively. Non-hematologic toxic effects were well tolerated, but grade 3/4 leukopenia occurred in 11.7% of all cycles. Four patients developed febrile neutropenia and one patient died due to pneumonia. Conclusions: This chemotherapy regimen was moderately effective for relapsed/refractory extranodal NTCL, nasal type. Toxic effects were moderate, but caution should be exercised to prevent severe infection.