Single unit recordings were made in the Deiters' nucleus of cats in response to electrical stimulation of the superior area of the contralateral saccule and the ipsilateral oculomotor (IIIrd) nuclear complex. Correct placements of the stimulating and recording electrodes were identified by upward movements of the eyeballs associated with characteristic field potentials in the Deiters' nucleus. Stimulation of the contralateral saccule induced a negative N wave followed by positive P1 and P2 potentials. One hundred twenty-two units responded to contralateral saccular stimulation with a mean latency of 2.48 +/- 0.06 msec (SEM). Of these, only the responses of 31 cells could be made to collide with antidromic spikes evoked from ipsilateral IIIrd nuclear stimulation. This implies that the crossed sacculo-ocular pathway would involve at least four neurons with one commissural cell interposing between the bilateral vestibular nuclei.