The hammerhead shark Sphyrna lewini (GRIFFITH & SMITH, 1834) is a cosmopolitan species of coastal and oceanic habits belonging to the order Carcharhiniformes. The head, compressed dorso-ventrally and laterally expanded in a cephalofoil, correspond to a morphological peculiarity in relation to the other species, resulting in large olfactory organs. Given the peculiar morphology of the head and the relevant potential of the hammerhead shark for navigation in two distinct marine environments, we postulate that this particularity may be reflected in the architecture of the olfactory bulb and the peripheral olfactory organ (the olfactory rosette) as an olfactory adaptation of this species to its habitat. Therefore, this work examined these structures by light microscopy (LM) and scanning electron microscopy (SEM). The olfactory bulbs are macroscopically long and cohesive, with no swellings or subdivisions. Histological analyzes showed a conjunctive peripheral layer, a glomerular layer and a layer of nerve bundles supported by an extensive mass of mitral cells. Olfactory rosettes consist of a number of lamellae (not determined) covered by sensory olfactory epithelium arranged in a column, composed of large and elongated receptor neurons that present microvilli in the apical region, rounded basal cells and a basal lamina of support. Although the structures that make up the olfactory system of the Sphyrna lewini are large macroscopically and with greater sensory epithelial surface area, there is no direct evidence correlating the size of these structures to the olfactory sensitivity.