The use of thoracic irradiation in the treatment of "limited disease" small-cell lung cancer yields better local control and survival rates than chemotherapy alone, according to meta-analysis studies of randomized clinical trials. Outside experimental studies, however, the role radiotherapy can currently play in the management of this type of cancer is difficult to assess because treatment modalities and patient selection criteria differ greatly. We report on the treatment outcome obtained in the Radiotherapy Department of the University of Siena in a series of 86 patients with small-cell lung cancer consecutively referred, January 1986 to January 1992; after a thorough staging, 46 of them were diagnosed as having a "limited disease". A "sequential" chemo-radiotherapy combination was used: irradiation was delivered after the completion of the initial drug treatment. Twenty-four patients (52.5%) achieved a complete and 22 (47.5%) a partial objective remission after chemotherapy, with acceptable early toxicity rates and severity. Twenty-eight of them received irradiation according to the following selection criteria: objective remission after chemotherapy (19 of 24 complete responders, excluding those with initial pleural effusion or worsening medical status during chemotherapy) and initial large tumor bulk (9 of 22 patients in partial remission). The overall treatment outcome rate (median survival: 18 months, 2-year survival: 28%) is in agreement with that of similar previous studies; toxicity rates are also similar (2% of treatment-related deaths). Survival analysis, according to "performance status" score, chemotherapy schedule and the achievement of complete remission with the initial drug management, exhibited significant differences only relative to the latter parameter. Many recent clinical trials suggest that combined chemo-radiotherapy could improve these results: toxicity is however reported as heavy, with this approach. Some guidelines are here considered, which could make this combination reliable also for current clinical use.