The olfactory epithelium of adult Labeo bata (Hamilton) has been studied by light and scanning electron microscopy. The oval shaped olfactory rosette consists of 26 to 28 primary lamellae arranged on both side of the median leaf like raphe. The middle dorsal portion of the lamellae is provided with linguiform processes. This linguiform process is occupied by sensory epithelium and characterized by the presence of two types of receptor cells, ciliated and with microvillous cells. The apical and basal part of the olfactory lamellae are covered with non-sensory epithelium. The non-sensory epithelium is made up of stratified epithelial cells and mucous cells. The surface of the non-sensory epithelium is represented by stratified epithelial cells which are provided with unbranched microridges arranged in a concentric whorl. Variations in the cellular organization in the sensory and non-sensory olfactory epithelium have been highlighted in reference to the olfactory sense of the fish concerned.