Objective To clarify the morphological features, types, regional distributions and cell densities of gastrointestinal endocrine cells in various parts of the digestive tracts of Canis lupus and Canis familiaris. Methods Immunohistochemical techniques of streptavidin peroxidase (SP) method was used. Results Seven kinds of gastrointestinal endocrine cells were found positive in the digestive tracts of Canis lupus and Canis familiaris. The endocrine cells were mainly located between the epithelia cells of gastric gland, intestinal villus and intestinal gland. There were also some endocrine cells distributed in the lamina propria and submucosa. The endocrine cells found in the digestive tract were in various shapes. Most of the endocrine cells had long cell processes run ning out to the lumen or the nearby cells. Among these endocrine cells, 5-hydroxytryptamine (5-HT) positive cells had a widest distribution, followed by vasointestinal poplypetide(VIP) positive cells. The distributions of other cells were limited. From the comparison of the characters of endocrine cells of Canis lupus and Canis familiaris, most of the endocrine cells had similar morphological features and regional distributions except pancreatic polypeptide (PP) positive cells and substance P (SP) positive cells. There were differences in cell densities of some endocrine cells.Conclusion The results of Canis lupus and Canis familiaris reflect the similarity of mammals in the characteristics of the morphological features, types