We measured high affinity glutamate uptake in subcortical projection sites of monkey (Macaca fascicularis) 8 weeks after unilateral ablation of Brodmann's areas 4 and 6. Uptake decreased ipsilateral to the lesion in ventrolateral nucleus of thalamus, caudate nucleus, and pons. Uptake also decreased contralateral to the lesion in cervical and lumbar spinal cord. These results suggest that L-glutamate (or possibly L-aspartate) is a neurotransmitter of corticofugal fibers in primate.