The role of the lateral reticular nucleus and inferior olive in production of the cerebellar cortex evoked potentials to stimulation of n. vagus was studied on 28 cats under chloralose-nembutal narcosis. After electrolytical destruction of the lateral reticular nucleus prolongation of the latency and a decrease in the evoked potential amplitude were observed, especially ipsilaterally. After bilateral destruction the potentials could be depressed completely. A conclusion is made that the lateral reticular nucleus provides a relay to to the cerebellar cortex of interoceptive vagal impulses. Appearance of predominantly simple discharges of the Purkinje cells responses to vagal stimulation is considered as an additional evidence for such a role of the lateral reticular nucleus. After damaging the inferior olive the evoked potentials arose with unchanged latency but reduced in the amplitude. Significance of the inferior olive as an intensity regulatory for the interoceptive impulse flow to the cerebellum is discussed.