Analysis of trace elemental concentration in the water of the São Francisco River located in the western part of the Brazilian state, Paraná, has been carried out using particle induced X-ray emission (PIXE) technique. The main objective of this work was to characterize and to monitor trace elements in the water of the São Francisco River, as well as to provide valuable information about the levels of metallic ion pollutants. Due to the detection limits of the PIXE analysis, up to 10 elements were quantified. Present work is a first attempt to identify trace elements of the São Francisco River. The highest total concentrations of Cr, As, Cu and Zn, detected in the river water are above the limits recommended by the Brazilian Environmental Legislation. The occurrence of these elements above the prescribed limits indicates the necessity of using improved techniques for industrial waste treatment. © 2006 Akadémiai Kiadó.