The aim of this study was to describe and comparison the histological features of the small intestine of rabbit that was herbivorous and rat that was omnivorous. The study was carried out on (10) samples of the small intestine of health adult local rabbit and rat, immediately after slaughtering, the samples were taken from the different parts of (duodenum, jejunum, and ileum), five specimens was taken from each region and fixed in 10% formalin for 24 hours, then treated by routine histological technique and the sections were stained by H &E, PAS, Toluidine blue, Safranin O, and Masson's trichrome to differentiate their different components. The present study showed the mean total thickness of the mucosa tunica in rabbit small intestine was thicker than that in rat, the duodenum had maximum thickness of the mucosa. The villi were variable in the appearance, high and wide; shape of the villi in the duodenum, jejunum and ileum in rabbit were taller leaf- like, conical and club shaped respectively, while in rat were taller finger, slender ridge and short finger like respectively; thickness of the submucosa tunica in rat small intestine was thicker than that in rabbit, the duodenum had maximum thickness of the submucosa; in rabbit the Brunner glands found in the submucosa of initial parts of the duodenum only, and absent in ascending part of duodenum, while in rat these glands extend near the jejunum, Peyer’s patch found through the submucosa of the ileum. Thickness of the muscularis and serosa tunicae in rabbit small intestine was thicker than that in rat, the ileum had maximum thickness each of \muscularis and serosa. There was difference in thickness of histological layers, also in shape and distribution of the villi and Brunner glands in the small intestine of rabbit and rat.