This randomized phase 2 study aimed to assess and compare the toxicity and response rates in patients with unresectable non-small cell lung cancer treated with radiotherapy (1.8 - 2 Gray [Gy] daily, five fractions a week, total 63 Gy) or radiotherapy + paclitaxel administered weekly (1.8 Gy daily, five fractions a week, total 59.4 Gy). Twelve patients in the latter arm received 30 mg/m(2) paclitaxel (median six cycles) over a 3-h infusion once weekly. After assessing toxicity, the remaining nine patients received 60 mg/m(2) paclitaxel weekly (median six cycles). Response was evaluated radiologically I month after treatment. Grade 3 toxicity was 20% and 38% in the radiotherapy and chemoradiotherapy groups, respectively. Overall survival rates in complete and objective (complete plus partial) responders and progression-free survival rate of the objective responders were significantly better in the chemoradiotherapy arm. We believe that using paclitaxel in concurrent chemoradiotherapy regimens may be effective in patients with unresectable, locoregionally advanced non-small cell lung cancer.