The binding of [3H]D-aspartate ([3H]D-Asp) to human cerebellum homogenate was compared with the uptake of [3H]glutamate ([3H]Glu) by homogenates prepared from rapidly frozen human cerebral cortex. There was a close correlation between the potencies of a range of drugs for inhibiting the binding of [3H]D-Asp and the uptake of [3H]L-Glu. Compounds selective for postsynaptic Glu receptors were inactive. The findings are consistent with the labelling of high-affinity Glu uptake sites by [3H]D-Asp, which may be a valuable ligand for studying excitatory amino acid terminals in human brain.