Abstract: To evaluate the role of post-operative radiotherapy ( PORT ) in the treatment of stage I-III small cell lung cancer ( SCLC ) after surgery, as well as to study the indication of PORT in patients with stage I-III SCLC. Methods: Patients with stage I-III SCLC treated with surgery in Tianjin Medical University Cancer Institute and Hopital between January 1998 and December 2009 were retrospectively analyzed, and the effect of PORT on their prognosis was evaluated. Out of the eligible 98 patients, 39 patients had pathological stage N0 disease, 22 had N1 disease, and 37 had N2 disease. As to the treatment, 8 patients underwent surgery, 41 patients underwent pre-operative chemotherapy, 86 received post-operative chemotherapy, and 39 of patients received post-operative radiotherapy. Kaplan-Meier and Cox regression model were used to analyze the role of PORT. Results: The median survival for the whole group was 34 months, and the 3-year overall survival ( OS ) was 45.8%. Both the univariate and multivariate analyses showed that PORT did not significantly improve the overall survival, but significantly reduced local-regional recurrence. The 3-year OS for the PORT and non-PORT group were 49.7% and 39.3%, and the median survival were 36 months and 30 months, respectively ( P = 0.260 ). The 3-year local-regional recurrence rate were 7.7% and 28.8%, respectively ( P = 0.001 ). The 3-year OS for pN0 patients with and without PORT were 54.5% and 64.3%, respectively ( P = 0.705 ), were 53.8% and 33.3% for pN1 patients ( P = 0.067 ), and 46.7% and 22.7% ( P = 0.141 ) for pN2 patients. Conclusion: PORT could reduce the local-regional recurrence of SCLC significantly, as well as the improvement of the overall survival rate of lymph node positive patients. Moreover, PORT may be considered for patients that still have lymph node positive SCLC after surgery.