Abstract. Six cases of acquired duodenal diverticulitis (pseudodiverticula) were found in a flock of sheep over a short period of time. All the animals had duodenal lesions characterized by the presence of multiple saccular dilations filled with feed material. The mucosal surface was elevated by multiple small nodules that histologically corresponded to cystic dilatations of the duodenal glands, which likely caused the displacement, atrophy, and disappearance of the muscular layer, leading to pseudodiverticula. The gross appearance, microscopic findings, and epidemiological characteristics suggest that this is a different pathological process to that described for diverticula in animals to date.