Objective To investigate the efficacy and toxicity of postoperative radiochemotherapy compared with chemotherapy alone in the treatment of locally advanced gastric cancer. Methods A total of 83 patients with resected adenocarcinoma of the stomach were randomly assigned to postoperative radiochemotherapy group (RCT)(n=43) or chemotherapy alone group (CT)(n=40). Patients in RCT group received radiotherapy concurrent with capecitabine chemotherapy then followed by 4－6 cycles of FOLFOX4 chemotherapy. The total dose of radiation was 45 Gy. The dose of capecitabine was 1600 mg/m² per day. In the CT group, patients received 6－8 cycles FOLFOX4 chemotherapy. Survival was analyzed using Kaplan-Meier method and Logrank test. Results The follow-up rate was 96%. The number of patients who had a minimum of 2-,3-year follow-up time were 37,12 in the RCT group and 31,10 in the CT group. The 1-,2-,3-year local control rates for RCT and CT groups were 100%,97%,94% and 95%,87%,73%(χ²=4.54,P=0.033), respectively. The 1-,2-,3-year survival rates were 98%,86%,81% in the RCT group, with 93%,80%,64% in the CT group (χ²=3.96,P=0.047). The incidence of grade 3 hematological toxicity in the RCT and CT group was 23% vs 15%(χ²=0.93,P=0.630), and grade 3 gastrointestinal toxicity was 16% vs 10%(χ²=0.95,P=0.624). Conclusions Compared with chemotherapy alone, postoperative radiochemotherapy can improve survival of locally advanced gastric cancer patients with acceptable toxicities.