Two non randomized therapeutic trials have been conducted in oat cell carcinoma of the lung with limited disease. The first protocol combined chemotherapy (adriamycin, cyclophosphamide, VM 26, procarbazine) with mediastinal and supra-clavicular radiotherapy in classical fractionation (40 grays in 4 weeks). The second combined a more intensive chemotherapy (adriamycin, VP 16, methotrexate, cyclophosphamide) with an alternating radiotherapy (3 series of 15 grays). All patients received prophylactic brain irradiation. Preliminary results show a 9 month survival rate of 34 per cent and 62.5 per cent respectively. In addition, all patients in the second protocol presented a complete response at the end of the induction treatment. These preliminary data encourage proceeding with this kind of combined treatment.