Probiotics and their components have been used to improve growth performance and immunity, as well as intestinal health. This study evaluated the effect of different doses of Saccharomyces cerevisiae on the morphological properties of duodenums of rabbits. Twenty 6-7 weeks old male New Zealand White Rabbits were randomly allocated into three groups for 90 days. The first group (control group) received the basal diet, the second group received basal diet supplemented with S. cerevisiae at a level of 2g/kg of feed, and the third group was fed with S.cerevisiae live yeast culture added at 4.0 g/kg. At the end of the experiment duodenum segments were taken, fixed in 10% neutral buffered formalin and processed for histological examination. In this study, the total thickness of the mucosa, the height of the villi and depth of the crypts and depth of the glands of the duodenum were found to be longer with the increased yeast doses. However, there was no significant difference among the villus crypt ratio of the groups. In conclusion, the total thickness of the mucosa, villus heights, crypt depths and gland depths were increased significantly in both of the yeast groups of rabbits. Therefore, it may be proposed that administration of S.cerevisiae in either low or high doses may be used for intestinal health.