Introduction:Parkinson’s disease (PD) is chronic progressive neurodegenerative disease. In patients with Parkinson’s disease among other symptoms occur cognitive dysfunctions, which can be shown by P300 wave changes.Aim:The aim of this study was to demonstrate that patients with Parkinson’s disease have reduced amplitude and prolonged latency, longer than 300 ± 10 ms.Material and Methods:The study included 21 patient suffering from Parkinson’s disease. After reviewing the medical records and analyzes the inclusion and exclusion criteria, patients were subjected to the same procedure examining auditory cognitive potentials (P300 wave) and the results were analyzed and compared to reference value for healthy population.Results:We have shown that patients with Parkinson’s disease have prolonged P300 targeted and frequent stimulus latency compared to reference value for healthy population. From 21 patient 18 had a pathological P300 target stimulus amplitude, and even 20 patients had pathological P300 frequent stimulus amplitude.Conclusion:People with Parkinson’s disease have altered P300 which indicates the presence of cognitive dysfunction in these patients.