A consensus regarding standard adjuvant chemotherapy for curatively resected gastric cancer has not been obtained between Japan and the Western world. In order to evaluate the effect of a tegafur-based regimen (the most frequently used regimen in Japan) compared with a surgery-alone control, a meta-analysis was performed, investigating four clinical trials. After meticulous examination of each trial, trials with improper noncentralized randomization were excluded from the analysis. A total of 1197 patients were enrolled in the four relevant trials determined to be eligible for the meta-analysis (Nakajima 1984; Japan Clinical Oncology Group [JCOG] 8801, JCOG 9206-2, and National Surgical Adjuvant Study of Gastric Cancer [NSASGC], in which a tegafur-based regimen was used for chemotherapy and central randomization was performed. The endpoint was overall survival, and a common hazard ratio was estimated. The 5-year overall survival rates differed among the trials because of differences in the background disease status. But there was no heterogeneity (P = 0.235) of treatment effect. The estimated common hazard ratio was 0.75, with a 95% confidence interval of 0.58–0.98. The treatment effect of the tegafur-based agent was shown to be statistically significant (P = 0.037) compared with surgery-alone therapy (n = 1179). From the results of the above meta-analysis, it is suggested that chemotherapy with a tegafur-based agent after surgery can improve the survival of patients with curatively resected gastric cancer. The Global Advanced/Adjuvant Stomach Tumor Research through International Collaboration (GASTRIC) group is conducting two individual patient data meta-analyses, testing post-operative adjuvant chemotherapy for resect-able gastric cancer and chemotherapy for advanced gastric cancer. It is expected to determine and quantify the role of adjuvant chemotherapy in detail from the GASTRIC.