A method for the measurement of cerebral glucose uptake rate by in vivo 31P Magnetic Resonance Spectroscopy (MRS) is proposed. The initial rate of 2-deoxy-glucose (DG) uptake after DG administration is measured by the increase of 2-deoxy-glucose-6-phosphate (DG6P) signal at a chemical shift of 7.2 ppm with respect to phosphocreatine (PCr). The values for four different metabolic states of rat brain (two levels of epileptic seizures induced by bicuculline, nitrous oxide analgesia and pentobarbital anesthesia) were in good agreement with the previously reported ones by radioisotope methods. This method appears to be useful for measuring cerebral glucose uptake rate.