In gastric adenocarcinoma, high rates of loco-regional recurrences have been reported even after complete resection, and various studies have been tried to find the role of postoperative adjuvant therapy. Among them, Intergroup 0116 trial was a landmark trial, and demonstrated the definite survival benefit in adjuvant chemoradiotherapy, compared with surgery alone. However, the INT 0116 trial had major limitation for global acceptance of the INT 0116 regimen as an adjuvant treatment modality because of the limited lymph node dissection. Lately, several randomized studies that were performed to patients with D2-dissected gastric cancer were published. This review summarizes the data about patterns of failure after surgical resection and the earlier prospective studies, including INT 0116 study. Author will introduce the latest studies, including ARTIST trial and discuss whether external beam radiotherapy should be applied to patients receiving extended lymph node dissection and adjuvant chemotherapy.