A retrospective analysis of 79 patients with malignant lymphoma (ML) of the upper gastrointestinal tract in a series of 842 endoscopically verified malignant tumours is presented. There was a significant difference between carcinomas and ML: in the latter, macrosopic diagnosis was correct in more than 90%, while histologic evaluation of forceps biopsies was false negative in 23.2%. Guided brush cytology provided an unexpected gain of information in 35%. Gastroscopy should be performed even in symptomfree patients with ML. Errors of histologic evaluation can be avoided by wire loop biopsy. Extragastric involvement of ML was successfully demonstrated in 93% by 67-gallium scanning.