Unidirectional optokinetic training modifies the response pattern of bidirectional sinusoidal vestibular stimuli (pendular rotation), resulting in an initial response decline. The latter affects only slow phase velocity, whereas the former shows a frequency increase. Optokinetic training obviously has a facilitating effect upon vestibular habituation which cannot be induced by repeated sinusoidal vestibular stimuli alone. Peak frequency increase as well as slow phase velocity decrease of vestibular nystagmus, induced by optokinetic stimuli, are interpreted as a typical transfer mechanism across two sensory systems.