The aim of the present study was to investigate whether a combination of chemotherapy plus radiotherapy was able to increase the overall survival rates compared with chemotherapy alone in stage IB-III uterine serous carcinoma. A total of 1096 patients (593 who had not received radiotherapy, and 503 who had) with primary stage IB-III uterine serous carcinoma who underwent surgery and received chemotherapy were included in the present study. The Kaplan-Meier method and Log-Rank tests showed that radiotherapy did not increase 5-year overall survival rates compared with the no-radiotherapy groups (52.3 cf. 50.8%, respectively; P = 0.641). Cox regression analysis subsequently corroborated that radiotherapy did not affect the 5-year overall survival rate (P = 0.635). Patients who were aged ≥ 60 years had a higher mortality rate [hazard ratio (HR), 1.712; 95% confidence interval (95% CI), 1.385-2.117; P < 0.05]. The 5-year overall survival rates were found to be lower in the groups where the regional lymph nodes had not been removed (HR 0.645; 95% CI 0.508-0.821; P < 0.05). Chemotherapy plus radiotherapy was found to not be associated with improved 5-year overall survival rates. However, chemotherapy may be a better treatment option for patients with primary stage IB-III uterine serous carcinoma who have undergone surgery.