Proton induced X-ray emission (PIXE) is a spectroscopic analysis technique based on detecting the emitted radiation from an atom excited upon interaction with a high-energy proton. It has been used to quantitatively determine to ppm levels, the elements present in a variety of substrates including inorganic, organic and biological samples. The technique is particularly applicable to quantifying the inorganic materials present in rubber compounds: non-black fillers (clay silica, talc), oxides (magnesium, titanium, zinc), colbalt adhesion promoters and total sulfur The non-destructive nature of the experiment and facile sample preparation make PIXE measurements particularly useful when only small quantities of material are available. PIXE in conjunction with characterization techniques that-afford structural information of specific compounding ingredients, can afford precise analytical characterizations of rubber compounds.