The paper describes the application of x-ray diffraction (XRD) analysis to several samples which show the information available from the technique. X-ray fluorescence (XRF) spectrometry was used for the elemental analysis because it provides very complete information with minimal sample preparation and analysis time. Two samples were analyzed which illustrate the difference between the final products obtained from the incineration of a waste crankcase oil sample by pot vaporization and air atomization. Also analyzed were particulate samples from two commercial waste incinerators, as well as three samples from lead and copper smelters. Study results indicate that XRD, applied with XRF, can be an effective tool for the characterization of industrial process streams. Information gained from this technique can be used for process and pollution control equipment evaluation and for by-product disposal criteria.