Abstract : Obesity can cause respiratory disorders caused by the accumulation of adipose tissue and numerous cytokines produced by adipocytes. Tobacco smoking, on the other hand, is primarily associated with the occurrence of a wide range of lung diseases characterized by diffuse changes in lung tissue and a decrease in the respiratory volume of the lungs. This research was conducted to study the features of ultrastructural changes in the lungs of sexually mature male rats under conditions of experimental obesity and tobacco smoking to study the pathological changes in lung tissue both under the conditions of isolated exposure to obesity and tobacco smoking and in the case of their combined influence under experimental conditions. The total sample of experimental animals included 120 rats divided into four groups randomly: the control group (n=30) – conditionally healthy rats, animals were fed according to a standard diet; a group of rats exposed to isolated tobacco smoke influence (n=30); a group of rats with experimental obesity (n=30), and a group of rats with experimental obesity simultaneously exposed to tobacco smoking (n=30) – feeding using a high-fat diet with exposure in a chamber with tobacco smoke. The identified ultrastructural features of the lungs in the group of rats with experimental obesity and the group of rats with experimental obesity simultaneously exposed to tobacco smoking did not differ qualitatively, which suggests that the pathological changes in the lungs tissue ultrastructure developed regardless of the presence or absence of a direct damaging effect of passive smoking on the lung tissue.