Eighty-five consecutive patients, seen between 1970 and 1987, with primary gastric non-Hodgkin's lymphoma were studied to evaluate diagnostic findings and treatment results. At endoscopy three main patterns were recognized: ulceration (n = 21), diffuse infiltration (n = 16) and a polypoid mass (n = 26). Recently, the new technique of endoscopic ultrasonography was used to measure depth of infiltration and regional lymph nodes. Preoperative diagnosis altered the indication of surgery. Since 1978 surgical staging was performed in only 29% of the patients compared to 90% in the earlier period. In the later period stage II was more systematically treated with a combination of chemotherapy and radiotherapy. Over the whole period patients in stage I (n = 52) had a 5 year disease-free survival of 63%. In stage II 38% had a 5 year disease-free survival. Complications were one perforation and one haemorrhage after radiotherapy and two cases of haemorrhage after radiotherapy combined with chemotherapy. Intraabdominal recurrences were found in two cases. Recognition of endoscopic features may lead to early detection and ultimately improved survival.