This article reviews the findings of event-related potentials (ERP) in Parkinson's disease (PD) published during the last 10 years. Basic principles and methods ofERP are briefly presented with particular regard to the auditory "odd-ball" paradigm almost uniquely employed for the ERP assessment in PD to date. The results of respective studies are overviewed and discussed with respect to three main axes:(1) The slowing down of cognitive processing in PD is reflected by the delays ofN2 and P3 components of ERP which are more important in demented than in non-demented patients. The Nl component is delayed in demented patients with PD as well as in other dementias of presumed subcortical origin. (2) Various neuropsychological deficits observed in PD correlate with the delays of ERP evoking the implication of common subcortico-cortical cerebral mechanisms. (3) The variations ofERP under dopaminergic manipulation suggest conflicting effects oflevodopa treatment on cognition, at least in certain categories of PD patients. These findings are discussed in the light of current knowledge on neurotransmitter brain systems and some hypothetic explanations are proposed. Finally, an attempt is made to outline further perspectives of clinical and research utilization of ERP in Parkinson's disease.