In the palliative treatment of advanced SCLC and NSCLC there is a big need for effective and well tolerable drugs. Bendamustin is an alcylatic agent which had shown activity in the treatment of Non Hodgkin- and Hodgkin-Lymphoma as well as in the treatment of solid tumors like Mamma-Carcinoma and Colorectal-Carcinoma. We treated 21 patients with NSCLC (5 pat. Stad. III b, 16 pat. Stad. IV) and 22 pat. with Extensive Disease SCLC with Bendamustin 70 mg/m2 i.v., day 1-4 (q.28 days). We observed a response rate of 40.9% in the patients with SCLC (9 PR/40.9%), (0 CR) and no response in the patients with NSCLC. Hematologic toxicity in both groups was mild (Leucopenia WHO 1 + 2: 13 pat./30.2%, WHO 3: 2 pat./4.6%; Anemia WHO 1 + 2: 13 pat./30.2%, WHO 3: 1 pat./2.4%; Thrombopenia WHO 1 + 2: 4 pat./9.6%, WHO 3: 1/2.4%). Non Hematologic toxicity consisting of Nausea/Vomiting (WHO 2 + 3:13 pat./30.2%), Diarrhea (WHO 2 + 3:3 pat./7%), Obstipation (WHO 1 + 2: 2 pat./4.6%), Fever (WHO 1 + 2: 9 pat./20.9%) and Alopecia (WHO 1 + 2: 13 pat./31.7%, WHO 3: 1 pat./2.4%) was well tolerable. Cardiac Arrhythmias occurred in 7 pat./16.3% and PNP in 2 pat./4.6%. Treatment had to be stopped in one patient because of an allergic skin reaction. Bendamustin is a well tolerable cytostatic drug with a remarkable activity in advanced SCLC which is comparable to other well known agents in the treatment of this disease. Because of the good toxicity profile a combination with other compounds might be feasible. In advanced NSCLC Bendamustin showed no activity.