The morphology of the small intestine of 39 fetuses and 13 neonates of Brazilian Moura pigs (Sus scrofa) was studied. Fetuses were collected on the 30th, 58th and 86th day of fetal life. The entire small intestine was removed and divided into proximal and distal regions (30th day), and into duodenum, proximal jejunum, distal jejunum and ileum on the 58th and 86th days and in neonates. On the 30th day, the small intestine was small and fragile and there was no visible delimitation among the three segments. The length and diameter of the intestine increased significantly (p<0.001) from 58 days of gestation to parturition. The length of the small intestine, duodenum, jejunum and ileum increased 2.5, 1.2, 2.6 and 3.0 fold, respectively, whereas the diameter increased 2.7, 2.4, 2.7 and 3.0 fold from 58 days of gestation to parturition. On the 30th day, the immature small intestine consisted of mesenchyme and stratified columnar epithelium. On the 58th day, the mucosa, muscularis circular, muscularis longitudinal and serosa were observed in the three segments of small intestine and there were no crypts in the distal jejunum and ileum. Goblet cells were common in the duodenum and rare in the jejunum and ileum. Brünner’s glands were observed in the submucosa. In 86-day fetuses, the presence of incipient myoblasts indicated that the muscularis mucosae was in formation. Crypts were observed in the three segments of the small intestine. In neonates, the muscularis mucosae was present and Brünner’s glands were more frequent. Peyer’s patches were observed in the ileum. These results show that the temporal development of the small intestine of Moura pigs is similar to that of modern breeds. However, macroscopic findings indicate that Moura fetuses have a longer small intestine and heavier body weight at birth than modern breeds.