The current study aimed to determine the localization and density of some peptides found in the digestive tract mucosa of Scardinius erythrophthalmus (Rudd). In accordance with the immunohistochemical examinations, it was observed that CCK immunopositive cells were found in the parts of the intestine except for the stomach. While gastrin immunoreactive (+) cells were not observed in the stomach and middle intestine region, a small amount of these cells were detected in the anterior intestine. In the posterior intestine, a very low density of gastrin immunopositive cells were detected. It was determined that glucagon immunopositive cells were found in very small amounts in the parts of the intestine except the stomach. While low density of somatostatin immunoreactive cells were observed in the stomach region, these cells were not found in the intestinal regions. In general, it was concluded in this study that the studied peptides were found in different concentrations in different parts of the intestine.