The esophagogastric junction was evaluated macroscopically and histologically, seeking to identify adaptive changes in a sample of six adult horses, being four males and two females, used for traction. The mucosa of the esophagogastric junction region was evaluated macroscopically with regard to the staining and the presence of ulcers. Tissue samples from this region were subjected to the conventional histologic technique and stained with Hematoxylin-Eosin. Aiming to measure the thickness of the keratinized stratified squamous epithelium, the software ProgRes® Capture Pro 2.5 was used. It was possible to observe ulcers in four animals, they presented themselves in the form of countless millimetric erosions along the margo plicatus, with an approximate diameter of 0.5mm, and a lesion extending from the margo plicatus to the esophagogastric junction region measuring 14.2 x 2.7cm. It was found that the average thickness of the keratinized stratified squamous epithelium, measured with an increase of 10x, was 104.9μm+31.98. A particular arrangement for each animal was observed, and it was proved through statistical analysis (ANOVA) and Tukey’s test, thus revealing the morphological adaptation of the region.