Background: The role of adjuvant chemoradiotherapy (CRT) in the treatment of gastric cancer patients after D2 resection has not been defined yet. This trial was designed to compare capecitabine plus oxaliplatin (XELOX) versus XELOX combined with concurrent CRT in the treatment of gastric cancer patients after D2 gastrectomy. Methods: Patients with histologically confirmed gastric cancer with T3-4/N1-3 after D2 gastrectomy were enrolled and randomly assigned to XELOX for 6 cycles (CT arm) or 2 cycles XELOX plus 45 Gy radiotherapy (RT) with capecitabine concurrently, and then followed by another 4 cycles of XELOX after RT (CRT arm). The primary end point was 3-year disease-free survival (DFS), and the secondary end point was 3-year overall survival (OS). Results: From January 2013 to June 2017, a total of 144 Patients were protocol eligible with 74 assigned to the CT arm and 70 to the CRT arm, respectively. With a median follow up of 25.6 months, the 3-year DFS and OS rates were 76.3% and 79.6% in the CT arm, versus 72.8% and 70.9% in the CRT arm, respectively. The addition of RT did not show significant differences on the DFS (P = 0.868) and OS (P = 0.683). The rate of local recurrence-free survival and distant metastasis at 3 years were 98.5% vs. 91.7% (p = 0.281) and 18.7% vs. 18.1% (p = 0.606) for the CT and CRT arms, respectively. For patients with positive lymph nodes (84.5%), the 3-year DFS rate was 70.7% and 71.1% in the CT and CRT arms, respectively. The DFS was a bit shorter in the CT arm than in the CRT arm but without statistical difference (p = 0.920). Common grade 3/4 AEs with chemotherapy and RT were leukopenia, neutropenia, thrombocytopenia. All patients finished at least 4 cycles of XELOX with 82.1% and 75.5% patients in the CT and CRT arms finished 5 cycles of chemotherapy. Conclusions: No significant benefits on DFS and OS of CRT observed in the treatment of gastric cancer after D2 gastrectomy. Addition of RT did not show significant on lowering the risk of local recurrence for gastric cancer patients. Adjuvant CRT needs further investigation with larger populations for gastric cancers patients after D2 gastrectomy. Clinical trial information: NCT01711242