We evaluated the diagnostic criteria of gastric lymphoma in endoscopic biopsies. METHODS Our study included cases diagnosed as lymphoma by gastroendoscopic biopsy between 1984 and 1994 that were available in the files of the Department of Gastroenterology, Chinese PLA General Hospital. RESULTS Among 53,400 cases of gastroendoscopy, we found 1672 (3%) cases of malignant neoplasm that were diagnosed by endoscopic features and histological findings. Thirty-eight cases of primary gastric lymphoma included 22 men and 16 women 16 to 82 years old, with a median age of 47.7. The endoscopy showed the ulcerative type in 12 cases, diffuse infiltrating type in 11 cases, massive infiltrating type in 6 cases, and large mucosal folds type in 4 cases. Five cases had a mixed type pattern of involvement. Histologically, 34 cases showed mucosa-associated lymphoid tissue lymphoma (89.5%), 2 cases had lymphoblastic lymphoma, and 2 cases were unclassifiable because of crush artifact of neoplastic cells. The majority of cases of primary gastric lymphoma have morphologic and clinical features that justify their inclusion in the category of low-grade lymphoma of mucosa-associated lymphoid tissue (MALT).