From March 1991 to June 1993 50 patients with local advanced NSCLC (mediastinoscopy obligatory) have been entered into an ongoing trial with preoperative chemotherapy and simultaneous chemo-/radiotherapy, followed by re-mediastinoscopy and surgery. Clinical response rates after chemotherapy amounted to 66.8% after chemo/radiotherapy 77.5%, no severe toxicity was observed. 36 patients ultimately underwent operation, 29 with a curative, 5 with a palliative resection and 2 with an explorative thoracotomy. Pathological complete remission rates of the primary tumor were found in 11 (32.3%), R0-resection in 18 (52.9%) and R1-resection in 5 (14.7%) cases. Sterilisation rates of mediastinal nodes were found in 86.3% of N2 tumors and 66.6% of N3 tumors. Median survival time ranged between 21 months for stage III a and 16 months for III b disease. This intensive preoperative neoadjuvant treatment is tolerable and effective, the requirements for a randomised comparative trial was met.