Abstract A novel xanthated chitosan derivative was prepared by the chemical reaction of CS 2 under alkaline conditions. Spectroscopic studies like FTIR, 13C NMR, TGA and XRD, SEM, and EPR were used for its characterisation. The chemically modified chitosan (CMC) was evaluated for its adsorption properties for Cr(VI). For a 100 mg/L solution of Cr(VI), the uptake of Cr(VI) by CMC at pH 3, was found to be much enhanced (71 mg/L) compared to the control chitosan (49 mg/L). The CMC can be a potential adsorbent for tannery wastewater treatment.