The regional interrelationship between cerebral oxygen consumption (CMRO2) and cerebral glucose utilization (CMRGlc) was studied in normal subjects using positron emission tomography (PET) and the 15O steady-state inhalation and the [18F]fluoro deoxyglucose method. The use of standard sets of rate constants and the model lumped constant of 0.52 as well as the regional blood-brain partition coefficient for water and the blood volume correction for oxygen extraction fraction provided a CMRO2/CMRGlc ratio of 4.89 in the cortical gray matter, 5.27 in the basal ganglia and 5.82 in the centrum semiovale (white matter). The values of CMRO2/CMRGlc for the basal ganglia and the white matter were consistent with those reported for the whole brain with the Kety-Schmidt method. There was no significant difference in the CMRO2/CMRGlc between the basal ganglia and the white matter indicating the similar nature of in vivo oxidative metabolism of glucose in neuron-rich region and glial cell-rich region.