X-ray photoelectron spectroscopy(XPS) was carried out to analyse a commercially available octanedioic acidpowder.XPSspectra were obtained using incident monochromatic Al Kα radiation at 1486.6 eV. Snapshots and scans of C 1s and O 1s core level spectra are presented. The presence of characteristiccarbon and oxygen photoelectrons allows the use these results as a reference for dicarboxylic acids.