A method has been developed for producing reversible cooling of the cerebellum in awake, unrestrained rats. A technique is described for covering the cerebellar cortex with a piece of thin platinum foil. Cooling of the cerebellum in the awake animal was accomplished by placing granules of dry ice in contact with the foil. After the effects of cerebellar cooling had been observed repeatedly in the awake, unanesthetized animals, the rats were once again anesthetized in order that subcortical temperature changes could be measured. The magnitude of the temperature changes was correlated with distance from the foil. The temperature of subcortical cerebellar tissue 2–6 mm below the platinum foil dropped 10 C in 4–5 min after application of the dry ice.