Background: Patients with Parkinson’s disease have dizziness or vertigo occasion-ally. This study is aimed to clarify the mechanism. Methods: From July 1993 to June 1997, fourteen patients of Parkinson’s disease with dizziness or vertigo were subjected to a battery of neuro-otological tests. Seven of them performed posturography. Results: Thirteen patients had oculomotor abnormalities (93%). Twelve (86%) showed abnormalities in saccade test, ten (71%) in pursuit test, eight (57%) in optoknetic nystagmus test. Posturography revealed poor postural control whether with eyes open or closed. Conclusion: Involvement of oculomotor pathway and visuopostural loop is responsible for vertigo and poor postural control of patients with Parkinson’s disease.