We measured total tau protein concentrations in the cerebrospinal fluid (CSF) of 26 non-demented Parkinson's disease (PD) patients and 25 matched controls. When compared with controls, PD patients had similar CSF tau protein concentrations. These values were not correlated with age, age at onset of PD, duration of PD, scores of the Unified PD Rating Scale (UPDRS), and the Hoehn and Yahr staging, and were not influenced significantly by antiparkinsonian drugs. Our results suggest that CSF tau protein levels are apparently unrelated to the risk of PD.