PURPOSE: The primary gastrointestinal non-Hodgkin's lymphoma(GI-NHL) is the most common extranodal NHL. Surgery with postoperative radiotherapy or chemotherapy was tried with some success, but proper management guidelines have not been established n localized GI-NHL due to its rarity and the lack of randomized trials. So we designed this study to evaluate treatment results and the lack of randomized trials. So we designed this study to evaluate treatment results and prognostic factors in localized GI-NHL, and to assess proper treatment modality after surgical resection according to risk factors by survival analysis. METHODS: Seventy three patients who received surgical resection due to localized GI-NHL from Jan. 1976 to Apr. 1991 were reviewed in this study. Prognostic factors were analyzed by multivariate analysis program including postoperative treatment methods, and treatment results were compared according to prognostic factors and treatment modalities. RESULTS: Overall 5-year survival rate was 62.3% for all patients. The 5-year survival rate was 86.0% for patients with stage I GI-NHL and 45.7% for those with stage II. Chemotherapy or not, stage and residuum or not after surgical resection showed significant survival benefit. In patients with high risk factors such as stage II or residuum after surgical resection, postoperative combined chemotherapy and radiotherapy showed better survival than those treated with single modality. CONCLUSIONS: Chemothrapy or not, stage, and residuum or not were important prognostic factors of patients with localized GI-NHL after surgical resection. Either chemotherapy or radiation therapy alone after surgical resection is recommended for patients without high risk factors(stageII or residuum after surgical resection) but the postoperative combined chemotherapy and radiotherapy seems to be beneficial for patients with high factors.