5-FU has been a key chemotherapeutic agent in the treatment of advanced or recurrent gastric cancer. In order to enhance the effect of 5-FU, biochemical modulation or combined chemotherapy has been developed. Although several phase III studies have been reported in 1990's, a standard chemotherapeutic regimen has not been established worldwide. Recently, newly developed anticancer agents such as CPT-11, TS-1, Paclitaxel, or Docetaxel can be clinically used for advanced gastric cancer either single agent or in combination that may further improve the quality of life and prolong the survival of patients with gastric cancer. In Japan, postoperative adjuvant chemotherapy has been actively developed to enhance survival benefit of surgery for patients with gastric cancer. There were a few positive single randomized controlled study showing benefit of adjuvant chemotherapy with a high evidence level. However, all reports of meta-analysis of adjuvant chemotherapy for gastric cancer indicated the survival benefit of adjuvant chemotherapy. At present, a nation-wide randomized controlled study in the postoperative adjuvant setting for gastric cancer using TS-1 (ACTS-GC) is under way that may clarify the effect of postoperative adjuvant chemotherapy in gastric cancer.