In this study, we evaluated the effect of chemotherapy (CT) and thoracic radiotherapy (RT) integration and the timing of RT on survival of elderly patients with limited-stage small-cell lung cancer. Eighty patients were retrospectively analyzed. All the patients revived thoracic RT and 70 patients received >2 cycles of CT. Twenty-two patients received RT sequentially to CT, 19 with RT consolidated with CT, and 29 with RT concurrent with CT. Early chest irradiation was defined as beginning RT after 1-3 cycles of CT (n = 44), and late chest irradiation was defined as occurring after >= 4 cycles of CT (n = 26). Twenty-six patients (32.5%) achieved complete response, 37 (46.2%) partial response, 10 (12.5%) stable disease, and 7 (8.7%) progressive disease. The median survival time for all patients was 19 months. The 1-, 2-, and 3-year overall survival (OS) rates were 68.9%, 41.3%, and 31.7%, respectively. In univariate analyses, the volume of the primary tumor, CT, treatment modality, timing of RT, target volume, and RT dose were significantly associated with OS. At 3 years, concomitant chemoradiotherapy was superior to consolidated and sequential chemoradiotherapy (40.0% vs. 36.9% vs. 40.0%, respectively). The rate of OS at 3 years was 37.1% for patients receiving early-RT and 27.8% for those receiving late-RT (P = 0.006). Multivariate analysis showed that CT and RT dose were independent factors influencing OS. Concurrent chemoradiotherapy resulted in a high survival rate. A radiation dose-response relationship was observed, and a dose of at least 60-Gy daily radiation demonstrated improved survival.