Standardized 8-mm mucosal wounds were made in the rat stomach at the rumeno-fundic junction, fundus, fundo-antral junction, and antrum, and examined at intervals up to 8 months. All wounds at the rumeno-fundic junction and fundus were healed within 4 weeks and at the antrum within 12 weeks. The majority of wounds at the fundo-antral junction remained chronic and at 8 months 41 of 50 rats still had ulcers 2 mm or greater in diameter. These findings suggest that the fundo-antral junction is an area which is susceptible to the development of chronic ulcers. This is a simple and reliable method of producing chronic gastric ulcers and does not alter the continuity or disturb the function of the gastrointestinal tract.