The olfactory organs of six teleost fish species were studied using scanning electron microscopy. Differences were found in number and arrangement of lamellae in the olfactory rosette, and five types of arrangement were distinguished. Four types of arrangement of sensory and indifferent epithelium were established in rosettes of the species studied. Differences in organization of the sensory epithelium in teleost fish species are seen in quantitative relationships of different receptor and secretory cells. In teleost fish, flagellar receptor cells were most numerous. In the sensory epithelium of flounder, separate flagellae distinguishable from ordinary flagella of receptor and supporting cells by their large size and membrane structure, were described. Secretory cells were observed in sensory and indifferent epithelium as dark openings which often occurred in marine teleosts, mediosmatics. In some species (greenling, sea bullhead), the openings look like wide craters and may be stomata of secretory ducts of the epithelial olfactory glands described earlier.