[(11)C]-PIB positron emission tomography ([(11)C]-PIB PET) is a sensitive marker of amyloid in Alzheimer's disease (AD), but its specificity has not been fully evaluated. Vascular amyloid-beta deposition is common in Parkinson's disease (PD) and alpha-synuclein, the major component of the Lewy bodies in PD, forms amyloid fibrils. We investigated five apparently cognitively normal PD patients with [(11)C]-PIB PET. The results were compared to 16 patients with AD and six healthy controls from a previous study. [(11)C]-PIB retention was not significantly increased in our patients who all had early stage PD. Further studies of more advanced PD patients are warranted.