Autoradiography of inhibitory and excitatory amino acid neurotransmitter binding sites in the cervical spinal cord of M. fascicularis spinal cord revealed inhomogeneous distribution of all binding sites in spinal gray matter. Quisqualate-sensitive [H-3]glutamate binding, [H-3]MK-801 binding, benzodiazepine binding, kainate binding, and GABA(B) binding had highest levels in the superficial layers of the dorsal horn (laminae 1 and 2) and substantially lower levels in other laminae. [H-3]Strychnine binding was more uniformly distributed throughout all laminae with highest levels in the superficial layers of the dorsal horn. These results are similar to those found in other mammals.