Abstract : This paper describes a technical analysis of biological samples of sweat by proton induced X-ray emission (hereafter referred to as PIXE). The choice of the irradiation conditions, the preparation of the targets, and the processing treatment of spectra are described. Two excitation systems were used, one under vacuum and the other in atmospheric pressure under helium. Advantages and disadvantages of the two systems are described and detection limits obtained in both cases are presented. A comparison with results obtained by X-ray analysis induced by radioactive sources is made.