Low-grade non-Hodgkin's lymphomas (NHL) are very sensitive to a broad range of chemotherapeutic and biological agents. Relapses, however, occur even after aggressive cytostatic combinations in first-line therapy. Therefore, effective and well-tolerated salvage therapies are very important. In this single-institution trial, the efficacy and toxicity of bendamustine in the treatment of relapsed low-grade NHL was investigated. Fifty-eight patients with low-grade NHL pretreated with different cytostatic regimens were included. All patients received bendamustine at 120 mg/m(2) as a 1-h infusion on 2 consecutive days. The treatment was repeated every 3 weeks until complete remission (CR), partial remission (PR) or stable disease (SD) was confirmed on two consecutive cycles. Efficacy and toxicity were evaluated in 52 patients: CR was induced in 11%, PR in 62% and SD in another 10% of the patients. No response to treatment was seen in 17%. The median duration of remission was 16 months and the median survival time was 36 months. Side effects were generally mild, and restricted to myelosuppression, gastrointestinal toxicity and allergic reactions. Bendamustine proved to be very effective and was well tolerated in pretreated patients with relapsed or primary resistant low-grade NHL.