Two binding sites for L-[3H]glutamate were tentatively localized in rat fascia dentata by determining the effects of selective lesions on specific binding. Both destruction of dentate granule cells with colchicine and ablation of the ipsilateral entorhinal cortex markedly reduced radioligand binding to a quisqualate-sensitive site (GLU A), but only the entorhinal lesion significantly reduced binding to a site that is less sensitive to quisqualate (GLU B). These results suggest that GLU A binding sites are localized mainly on the dentate granule cells, whereas GLU B binding sites are localized, in part, on the perforant path fibers, but not on granule cells.