Docetaxel has shown remarkable radiosensitizing in vitro properties. In a previous phase I/II dose escalation study in non-small-cell lung cancer (NSCLC) we observed a high response rate after concomitant boost radiotherapy and weekly docetaxel. The maximum tolerated dose was 30 mg m(-2) week(-1). In the present phase II study we evaluated whether weekly docetaxel and conventionally fractionated radiotherapy could be better tolerated and equally effective in the treatment of locally advanced NSCLC. Thirty-five patients with T3, T4/N2, T3/M0-staged disease were recruited. Docetaxel (30 mg m(-2)) was given as a 30 min infusion once a week. Asthenia and radiation-induced oesophagitis were the main side-effects of the regimen enforcing 2-week treatment delay in 6/35 (17%) patients and minor delay (3-7 days) in another 11/35 (31%) patients. Neutrophil, platelet and haemoglobin toxicity was minimal, but pronounced lymphocytopenia was observed. Complete response (CR) of the chest disease was observed in 12/35 (34%) patients and partial response in 16/35 (46%). Although not statistically significant (P=0.19), a higher CR rate (8/18; 44%) was observed in patients who accomplished their therapy within the scheduled treatment time (44-47 days) as compared to patients that interrupted their treatment for several days due to treatment-related toxicity (CR 4/17; 23%). The overall survival and the local progression-free survival at 1 year was 48% and 60% respectively. We conclude that docetaxel combination with radiotherapy is a promising approach for the management of locally advanced NSCLC that results in high CR rate. Further trials with docetaxel-based radiochemotherapy should integrate accelerated radiotherapy together with cytoprotection.