Peculiarities of morphofunctional changes of the wall of the small intestine in experimental animals during the development of streptozotocin diabetes mellitus, against the background of chronic immobilization stress and under the combined effects of these pathological conditions were studied. Objective – to evaluate the features of morphofunctional reconstruction of the small intestine of rats in experimental streptozotocin diabetes mellitus under chronic stress. Methods. Experimental adult rats were modeled for absolute insulin deficiency by intraperitoneal administration of streptozotocin at a dose of 7 mg per 100 grams of body weight. To simulate stress, the animals were subjected to daily rigid immobilization in special cages for 6 hours at different time intervals. In order to study the combined effects of these pathological factors, the animals were immobilized from the 14th day of diabetes mellitus. The material was taken 28 and 56 days after the start of the experiment. Results. During the development of experimental diabetes mellitus in the small intestinal wall of experimental animals, there is a predominance of enteropathy due to dystrophic changes in the intestinal wall. Focal signs of enteritis predominated during the 56-day simulation of chronic stress. With the combined effect of these pathological conditions on the 28th day of the experiment, focal signs of enteritis and enteropathy were observed, which progressed to 56 days of the experiment.Conclusions. On samples from the small intestine wall, stained with hematoxylin and eosin, in rats with experimental diabetes mellitus, mucosal atrophy was noted, which was manifested by shortening of the villi and an increase in the depth of the crypts. Against the background of chronic stress on the 28th day, the wall of the small intestine retained the normal histologic structure, with local signs of inflammation, but on the 56th day, there was significant leukocyte infiltration of the mucous membrane and submucosal layer, increased eosinophils, lymphocytes and histiocytes. In rats with diabetes on the background of stress, structural changes in the intestinal wall were characterized by the greatest polymorphism.