Purpose: We have carried out prospective randomized clinical trial to compare survival benefit and side effect among three postoperative adjuvant chemotherapeutic regimens in serosa-negative gastric cancer patients. Materials and Methods: Total 317 cases were recognized as serosa negative and randomized into three groups at operating room. Out of them, 172 cases were excluded because of various reasons and 135 cases were analyzed finally; Group A 36 cases, Group B 49 cases, Group C 50 cases. Group A were treated with intravenous FP combination therapy, group B with MF combination therapy and group C with oral $UFT^{(R)}$ (mixture of Tegafur and Uracil) for one year. The median follow-up period was 30 months. Results: $88.9\%$ of Group A, $83.7\%$ of Group B and $90.4\%$ of Group C received adequate chemotherapy. The complication rates of Group A ($44.4\%$) was significantly higher than group B ($20.4\%$) and group C ($24.0\%$)(P<0.05). Most frequent complications were nausea and vomiting. The 3-year survival rates and disease-free survival rates were $92.2\%$ and $89.9\%$ respectively (Group A: $96.6\%,;87.8\%$, B: $90.3\%,;87.7\%$, C: $95.7\%,;93.8\%$). There were no significant differences in survival rate and disease-free survival rate among the three groups (P>0.05). Conclusion: This study might suggest that the survival benefit of postoperative adjuvant chemotherapy for gastric Pseudomonas aeruginosa, and therefore it may be a useful adjunct tool for detection of Pseudomonas aeruginosa infection in combination with other conventional techniques.