In two randomized trials it was demonstrated that preoperative and postoperative chemotherapy shows a statistically significant and clinically relevant improvement in progression-free and overall survival for adenocarcinoma of the esophagogastric junction and stomach when compared with the surgical control arm. The absolute benefit in overall survival was 13% and 14% after 5 years. This benefit is clearly shown for patients with locally advanced tumors but remains debatable in early disease stages. Postoperative mortality and the complication rate were not increased. Based on published study results perioperative chemotherapy has to be regarded as the new standard of care at least for patients staged as uT3/uT4 tumors as defined by endoscopic ultrasound. To date there are no indications for adjuvant chemotherapy or chemoradiation after R0 resection and adequate surgery.