We apply the technique of X-ray photoelectron spectroscopy (XPS), a well established surface characterization technique (gives semi-quantitative and qualitative chemical speciation information) to the speciation of chromium ions in aqueous solutions through the analysis of residuals on selected substrates. Aqueous systems containing 1-50 ppm Cr (VI) and Cr (III) singly, and as mixtures were analyzed on anodically prepared alumina films and on Indium foil. XPS results are presented on the oxidation states of chromium ions in aqueous media. Binding energy shifts of core level 2p electrons at approximately 579 and 577 eV were identified for Cr (VI) and Cr (III) respectively. The interfacial chromium species on Indium metal shows a Cr3+ ion, irrespective of the oxidation state of the original Cr species in solution. This phenomenon was not observed on the alumina films. Photoelectron peaks identifying Cr (III) and Cr (VI) were also identified in aqueous systems containing <1 ppm Chromium