The retromolar mucosa of the rat, mouse and golden hamster was observed by light and scanning electron microscopy. Numerous taste bud papillae, each of which formed a low round eminence containing one to several taste buds, were present in the posterior region of the retromolar mucosa, and were especially concentrated in the vicinity of the orifices of the molar glands. This topographical coincidence suggests that the retromolar mucosa of these animals has a functional role as a taste organ. Microridges, arranged in various patterns and small pits, were observed on the surface of the keratinized epithelium of the rat and mouse retromolar mucosa. It appears that the development of numerous microridges is adapted for varied stimuli in the oral cavity.