For a long time, thoracic radiotherapy has been the standard treatment of stage III non-small cell lung cancer. Because of the low rate of cure and the high rate of metastases in this group, strategies that combine radiotherapy with chemotherapy have undergone extensive investigation during the past decade with both positive and negative results. The combined treatment can be administered either sequentially, concurrently, or in an alternating mode. Some of the randomized trials have reported a positive impact of the addition of chemotherapy to radiotherapy with a positive impact of 2 to 4 months in terms of median survival. New therapeutic strategies are needed in order to improve control of both local disease and distant metastases. Improved local control could be achieved with higher radiation doses, conformal radiotherapy, altered fractionation schedules and possibly adjuvant surgery. Control of extrathoracic micrometastases may be improved with new combined modality strategies and new drugs. Increased toxic effects of these combined modality treatments should not diminish the expected therapeutic efficacy.