Local glucose consumption within specific brain structures in awake and halothane-anesthetized primates was studied using a quantitative autoradiographic technique for glucose (14C-deoxyglucose). In both awake and anesthetized animals, significant heterogeneity (one-way analysis of variance) in uptake of glucose was found in the cortex, subcortical grey matter, and brainstem nuclei. No significant variability was found for any of the white matter areas sampled under either experimental condition. Halothane produced significant decreases in glucose metabolic rates in the occipital cortex, brainstem nuclei, cerebellar cortex, cerebellar white matter, and anterior commissure, compared with the awake state. The greatest decrease in cerebral metabolic rate was found in the occipital lobes of halothaneanesthetized animals. Results of this study suggest that neurophysiologic and behavioral changes that occur with anesthetic agents can, for the first time, be correlated with alterations in local cerebral glucose metabolism.