The morphology of the terminal ileum was studied in 33 male adult pigs of unknown breed. The ileum ended in the cecocolic junction at an acute angle to the cecum. The terminal ileum displayed a cylindrical form (63.6% +/- 8.4 of the cases) more frequently than an ampullary (21.2% +/- 7.1) and/or an infundibular form (15.2% +/- 6.2). The ampullary form is not related to the quadrupedal position of the animal, but is related to the functional phase of the intestine at the time of death. In the mucous tunica of the terminal ileum, longitudinal folds and aggregated lymphoid nodules appeared concentrated along the antimesenteric border.