Purpose: To explore the relationship between SER (time between the start of any treatment and the end of radiation therapy) and the survival of patients with limited-stage small cell lung cancer. Materials and Methods: Between 2008 and 2013, 135 cases of limited-stage small cell lung cancer (LS-SCLC) treated with consecutively curative chemoradiotherapy were included in this retrospective analysis. In terms of SER, patients were divided into early radiotherapy group (SER<30 days, n=76) and late radiotherapy group (SER >= 30 days, n=59) with a cutoff of SER 30 days. Outcomes of the two groups were compared for overall survival. Results: For all analyzable patients, median follow-up time was 23.8 months and median overall survival time was 16.8 months. Although there was no significant differences in distant metastasis free survival between the two groups, patients in early radiotherapy group had a significantly better PFS (p=0.003) and OS (p=0.000). Conclusions: A short SER may be a good prognostic factor for LD-SCLC patients treated with concurrent chemoradiotherapy.