Erectile dysfunction (ED) is a condition characterized by the inability to achieve or maintain an erection sufficient for sexual intercourse. The prevalence of ED ranges from 6% to 64% depending on age. Obesity is one of the factors leading to ED, which is widespread in the world. Men with obesity are 30% more likely to develop ED compared with men with normal body weight. The aim was to identify morphological changes in the cavernous tissue of the penis of patients with obesity using the biological model of laboratory rats as an example. In vivo modeling of diet-induced obesity was performed. A total of 22 laboratory sexually mature white rats weighing 140-160 g were included in the study. The animals were divided into two groups, the control group (n=10) and experimental group, which included rats with diet-induced obesity (n=12). After 12 weeks, the experiment was completed. All rats underwent: 1) calculation of the Lee index (body mass index in rats); 2) determination of blood glucose level; 3) determination of the level of total cholesterol and triglycerides in the blood; 4) sampling of the penis with fixation in 10% formalin; histological sections 6-8 m thick were stained with hematoxylin and eosin, and frozen sections were prepared with subsequent staining with Sudan 3 to identify adipose cells. In the experimental group, alimentary obesity developed. There were no differences in glucose and total cholesterol levels between two groups. However, a significant difference was found in the serum triglycerides level (1.24+/-0.05 mmol/L in the control group vs. 1.6+/-0.1 mmol/L in the experimental group). In the control group, the average number of adipocytes was 10+/-5 per sample; in the experimental group, their number increased by 3 times (p<0.01). In obese rats, there was an increase not only in the number of adipose cells, but also in their area compared with the control group (17.7+/-7.5 m and 12.9+/-5.3 m, respectively, p<0.01). In rats with alimentary obesity, deposition of adipose tissue is observed not only in the visceral and paratesticular regions, but also in the cavernous tissue of the penis, which can negatively affect erectile function.