The Authors have diagnosed by endoscopy and biopsy 33 primitive gastric lymphomas (6,7% of all malignant gastric tumors diagnosed over 6 years). Endoscopic observation alone diagnosed lymphoma in 63,6% of the cases. Exact diagnosis was made in all cases of polymorphic or multi-ulcerated lesions. The observation of a single ulcerated or ulcero-vegetative lesion (30,3%) suggested diagnosis of carcinoma. A false negative diagnosis of inflammatory pathology was made in 6,1% of the cases. Biopsy gave correct diagnosis in 69,7%. Highest percentage of positive biopsies was obtained in both single and multiple ulcerated lesions (88,2%), while infiltrating lesions provided positive biopsies in 50% of the cases. Endoscopy together with biopsy gave correct diagnosis in 90,9%. In fact, endoscopic diagnosis of lymphoma was confirmed after resection in 7 cases even if the individual biopsies showed superficial gastritis. The Authors believe that correct endoscopic study of primitive gastric lymphomas is based on knowledge of the various morphologies of the tumor and on a systematic performance of a large number of biopsies of both the lesions and surrounding mucosa.