ABSTRACT. This study deals with anatomical, histochemical and ultrastructural adaptations of the alimentary canal of the Uromastyx aegyptius and the Spalerosophis diadema to their food habits. Proteins and nucleic acids are highly pronounced in the alimentary tract mucosal cells of the studied two species. A variable distribution of proteins and nucleic acids was observed in the different regions of the alimentary tract mucosa of the studied two species. The activity of alkaline phosphatase showed obvious variations not only among different organs, but also between the two species. At the ultrastructural level, the oesophageal mucosal cells contained oval shaped euchromatic nucleus with condensed chromatin and the perinuclear cytoplasm contained some electron-light vesicles. The gastric mucosal cells contained oval shaped euchromatic nucleus with condensed chromatin and the cytoplasm contained many rough endoplasmic reticulum, also many tonofilaments formed thick bundles which converged at the adherence junction in the lateral membranes. The small and large mucosal intestinal cells contained oval euchromatic nuclei and their cytoplasm contained few electron-light vesicles, also their lateral membranes showed many interdigitations. In spite of their difference in taxonomy, habitat, mode of feeding and their vital activities, they show more or less a similarity in the histochemical and ultrastructural patterns of their alimentary tract mucosa. This study can be applied to distinguish between different species of reptiles and for establishment of natural reserves.