When treated by irradiation alone, non small cell carcinomas of the lung usually experience a very poor outcome. Consequently, more interest is being focussed on radiotherapy and chemotherapy association. The analysis of a randomized trial comparing irradiation alone to a sequential or an alternated combination of radio and chemotherapy did not reveal any clear advantage of the association of both therapies on each technique used alone. It is only when using concurrent irradiation and chemotherapy that some encouraging results are reported. Several non randomized studies used radio and chemotherapy prior to surgery, aiming at increasing the resectability rate. However, the criteria for initial unresectability were not homogeneous and it is not yet clear if such an association really allowed the state of surgical resection to be improved. In the near future it could be worth considering the use of radiosensitizing drugs, synchroneously given with an irradiation delivered with a multiple daily fractionation. This technique would possibly lead to a therapeutic gain, by increasing the local control rate and reducing the metastasis rate, while keeping it to an acceptable level of toxicity.