Gastric cancer is still a major health problem and a leading cause of cancer mortality despite a worldwide decline in incidence. Surgery is the primary curative treatment of locoregional gastric cancer. In Western countries, however, at the time of resection, most patients are expected to have regional lymph node involvement with poor prognostic implications. To improve these results, different trials have been carried out in the adjuvant or neo-adjuvant setting. Many phase III trials of adjuvant therapy have been conducted; however, postoperative treatment modalities have not proven to be superior to postsurgical observation alone. Therefore, at present the routine use of adjuvant therapy should be regarded as an investigational approach. Improved clinical trial designs with standardized surgical techniques and the incorporation of newer active drugs are needed. On the contrary, neo-adjuvant chemotherapy has shown promising results as suggested by the final results of UK Medical Research Council Adjuvant Gastric Infusional Chemotherapy trial.