This randomized phase III trial aimed to determine whether treatment with cisplatin and volume-directed radiation followed by carboplatin and paclitaxel for four cycles (chemoradiotherapy [C-RT]) increased recurrence-free survival (RFS) and overall survival (OS) when compared with carboplatin and paclitaxel for six cycles (chemotherapy [CT]) in locally advanced endometrial cancer (UC). Previously reported results showed that C-RT did not improve RFS compared with CT. Here we report the final OS analysis. Patients with International Federation of Gynecology and Obstetrics (FIGO) 2009 stage III-IVA UC or stage I/II serous or clear cell UC and positive cytology were enrolled. The primary objective was RFS. Secondary objectives were OS, toxicity, and quality of life. Cumulative probabilities of OS were estimated using the Kaplan-Meier method. Subgroup analyses of treatment effect for FIGO stage, age, race, gross residual disease, histology, lymph-vascular space invasion, and body mass index were performed. In total, 813 patients were randomly assigned (407 C-RT and 406 CT). The median follow-up was 112 months. Median OS was not achieved in either arm. The stratified hazard ratio for death comparing C-RT versus CT was 1.05 (95% CI, 0.82 to 1.34, log-rank two-sided