In three series the bioptical findings of ulcer scars were evaluated to compare the gastritic changes in active ulceration and during scar formation. Within 18 months there were virtually no alterations of the mucosal pattern whether recurrent ulcer, macroscopic scar formation or normal mucosa was found in the follow-up period of gastric ulcer. Incidentally found ulcer scars showed different gastritic changes in accordance with the ulcer scar location. Gastroscopic biopsy of just reepithelialized lesions revealed that following a monocellular epithelisation the temporary pattern of chronic atrophic gastritis takes place which finally end up in the preexisting type of gastritis. The scar formation in the submucosal layers seem to persist whereas the mucosa regenerates.