Objective - to characterize morphological changes in the colonic wall in experimental chronic colitis induced by dextran sulfate sodium (DSS). Material and methods. Experiments were carried out on sexually mature male C57B1/6 mice. Drinking water in the animal dishes was replaced by 2% DSS solution for 6 days and the animals were taken away from the experiment on day 21 after initiation of DSS consumption. Hematoxylin- and eosin-stained colonic histological specimens were prepared by Masson's trichrome and Nissl methods. Results. Histologically, the colonic wall displayed epithelialized ulcers; mucosal remodeling; reductions in the count of goblet cells, crypts and their depth; mucosal inflammatory infiltration with lymphocytes, plasmocytes, and histiocytes; lymphoid tissue hyperplasia; diffuse and focal sclerosis of all colonic membranes; neuronal destructive changes in the myenteric and submucosal nerve plexuses. Conclusion. The experimental model of DSS-induced chronic colitis corresponds to human colitis in morphological characteristics to a certain degree and may be used to study of the pathogenesis of this disease and to preclinically evaluate of the efficacy of medications.