In the paper we consider how proton-induced X-ray emission (PIXE), using high-energy protons (MeV), can be used as a nondestructive technique for studying impurities in silicon. The basic principles behind PIXE are presented and the PIXE system used is described. Concentrations of various impurities observed in silicon wafers have been determined and comparisons made with the spectrum obtained with the Rutherford backscattering technique.