The distribution and localization of acid and neutral mucins in various cells lining the olfactory epithelium of Cyprinus carpio have been studied histochemically by employing the PAS-AB technique. Variations in the localization of protein in different cells lining the olfactory epithelium have been correlated with the functional significance of the region concerned. Intense localization of the silver stain in the surface of the olfactory epithelium as well as in the central core confirms the presence of different types of neurons. The localization and functional variations of alkaline phosphatase (ALPase) and adenosine-tri-phosphatase (ATPase) in the cells lining the olfactory epithelium of C. carpio have been discussed.