Abstract   Histology offers a powerful tool in the study of detailed structures of different tissues in fishes. It is used for sex verification, identifying stages of development, presence of parasites, tumors diagnosis, other abnormalities and changes in the arrangement of tissue layers including the digestive tract. In this study, not having found any existing report, the digestive tract histology of the Persian tooth-carp, Aphanius persicus (Jenkins, 1910), was investigated. The dentition comprised canine-like teeth in one row with sharp tips. Esophagus consisted of small portion between pharynx and stomach. Stomach showed an enlargement and the intestine is relatively short. The mucosa of total digestive tube consisted of simple columnar cells and numerous goblet cells. The liver is composed of parenchymal cells and lattice fibers whose function is to support the former. Our data showed this fish is heterodont, omnivores with no secretory stomach.