The concentrations of Br, Cu, Fe, Se, Zn, Mg were determined by particle-induced X-ray emission (PIXE) in serum and cerebrospinal fluid (CSF) of 13 untreated, 7 L-dopa treated parkinsonian patients and 25 controls. There were significant positive correlations between serum concentrations and CSF concentrations of Br, Cu, Fe. The Cu/Zn ratio in the serum and the CSF/serum ratio of Br were significantly increased with age in normal controls. The mean CSF concentration of Mg in both treated and untreated parkinsonian patients was lower than in controls. PIXE is a valuable method for multielemental analysis of the serum and CSF.