62 patients with a limited small cell lung cancer were randomly qualified into two groups. 32 patients of the first group were treated only with the chemotherapy regimen, consisted of three drugs (Carboplatine, Etoposide and Vincristine administered in 6 courses, on regular, 3-weeks basis). The second group of 30 patients had been treated with the identical chemotherapy schedule, but alternatively combined with a primary site irradiation in a total dose of 40Gy, applied in parts after the chemotherapy courses 2, 3, and 4. The significantly higher proportion of a complete remission results was observed in the alternate-treatment group: 14/30 (46.7%), compared with the chemotherapy-only group: 10/32 (31%). Alternate chemoradiotherapy resulted both in the increased median remission duration time, and the increased median survival time. Only in the alternate chemotherapy group, in 14/30 patients (46.7%) the pneumotoxicity symptoms appeared, whilst no differences in other organ-specific treatment-induced toxic effects were noted.