Our experience with 66 endoscopic-bioptic diagnosed malignant non-Hodgkin's lymphomas (NHL) showed that in most of them (57 of 66 patients) a tumor stage IE or IIE was present. All 57 primary gastric lymphomas were B-cell-lymphomas arising from the mucosa-associated lymphoid tissue (MALT). After curative primary gastric resection in stage IE and IIE the 5-year survival rate was 81%, and the 5-years lymphoma-related survival rate was 88%. These results are superior to those reported in the literature. The following two points are probably of importance for improving the prognosis: early diagnosis made possible by better knowledge of the infiltrative-flat type of tumor growth (38 out of 57 patients, including 23 cases in which infiltration was limited to mucosa and submucosa = "early lymphoma"), and extensive preoperative staging. The infiltrative-flat type, which is difficult to diagnose endoscopically, usually shows low-grade malignancy on histology (76%; in early lymphoma 83%) and has an excellent prognosis when submitted to surgery. In our experience the question as to whether additional treatment by chemotherapy and/or radiotherapy improves the prognosis of NHL of the stomach remains unanswered and further studies are needed.