Abstract: The regional distribution and relative frequency of endocrine cells was studied immuohistochemically in the gastrointestinal tract of the frog, Rana ridibunda, using antisera against serotonin, somatostatin-14, cholecystokinin and vasoactive intestinal polypeptide. These immunoreactive cells were located in the gastric glands of stomach and in the intestinal epithelium with variable frequencies. They were spherical or spindle shaped. The regional distributions and relative frequencies of the endocrine cells in the gastrointestinal tract of the Rana ridibunda were resembled to those of the other anuran species.