Clinical trials of adjuvant chemotherapy after surgery of gastric cancer have a long history dating since the late 1950s, but no standard regimen is yet established. Early studies included 5-FU- or TSPA-based regimens, sometimes combined with Me-CCNU or BCNU in Western countries, and resulted in a negative survival benefit, whereas 5-FU or MMC alone, or in combinations such as with MFC, were tried in Japan, and resulted in marginal survival benefit in the subset of moderately locally advanced diseases. Oral administration of 5-FU or its derivatives characterized Japanese trials in 1980s, though no definite benefit is yet established. Recent reports from Western countries regarding ELF, MMC + TGF, and FEM suggest significant or subsignificant survival benefit after curative gastrectomy. Meta-analysis of randomized trials also suggested marginal significant survival benefit, and these results encourage future trials with new drugs. The same regimens administered following surgery with different technical skill may result in different outcomes, and treatments in our country should be established based on our trials.