Quantitative autoradiography was used for the localization of l-[ 3H]glutamate binding sites in chick brain. The highest concentration of these sites was observed in the molecular layer of cerebellum. High concentrations were also observed in the hippocampus, area parahippocampalis, neostriatum, neostriatum intermedium and hyperstriatum ventrale. In most areas binding of l-[ 3H]glutamate was increased when incubation was done in chloride-containing medium. This increase was statistically significant in only few of these areas.