Objective: In order to get more information about the possible functions of Calbindin D-28K in the central nervous system of adult cat, the distribution of Calbindin D-28K in the central nervous system of adult cat was examined. Methods: Immunohistochemical staining techniques were used, and immunostained sections were observed under a light microscopy. Results: A high density of both immunoreactive perikarya and fibers were observed in the basal ganglia, amygdaloid complex, nucleus of the fields of Forel, subthalamic nucleus, paracentral nucleus, pulvinar nucleus, subthalamus, dorsal hypothalamic area, lateral hypothalamic area, anterior hypothalamus, suprachiasmatic nucleus, superior colliculus, inferior colliculus, oculomo-tor nucleus, superior olivary complex, marginal nucleus of the brachium conjunctivum, vestibular nuclei, the spinal trigeminal nucleus, nucleus of the solitary tract, cuneate nucleus, inferior olivary complex, dorsal motor nucleus of the vagus nerve, the molecular layer of the cerebellum, the purkinje cell layer of the cerebellum and in the laminae Ⅱ of the spinal cord, whereas the dentate gyrus, the central medial nucleus of the thalamus, the paracentral and central lateral nucleus of the thalamus, the lateral dorsal nucleus of the thalamus,the ventrolateral complex of the thalamus, the medioventral nucleus of the thalamus, the posterior hypothalamic area, the dorsal hypothalamic area, the infundibular nucleus, the dorsomedial hypothalamic nucleus and the interfascicular nucleus had just a high density of immunoreactive perikarya, and no positive fibres were detected in these areas. Conclusion: The present results showed that Calbindin D-28K-like immunoreactivity was widely distributed throughout the central nervous system of adult cat and might play an important role in the activities of the neurons in the central nervous system of adult cat.