Increases and decreases of action potential (pulse) rate were observed in some single vestibular ganglion nerve cells of the guinea pig in response to pressure changes in the external auditory meatus. Minimum stimulus intensities necessary to elicit clear responses were in the range of 1-2 cm Hg. These results (1) support an hypothesis regarding mechanisms of vestibular activation by intense infra- and audiofrequency sound, and (2) suggest a new stimulus technique for neurophysiological investigations of the vestibular pathway and central sensory integration.