In the present era, due to industrial revolution in the developing countries like India, the ground water system has been largely polluted. Tannery effluent is a major source of aquatic pollution, and a large number of tanneries are scattered all over India particularly in Tamilnadu, Uttar Pradesh and West Bengal. This work deals with the removal of heavy metals chromium and lead and the reduction of the important physicochemical parameters like total dissolved solid (TDS), total suspended solid (TSS), total solids (TS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total hardness, salinity, turbidity and electrical conductivity from the tannery wastewater by using chitosan-g-poly(butyl acrylate)/bentonite nanocomposite as an adsorbent. The batch system was used to conduct the biosorption experiments. The influence of different experimental parameters, such as contact time, pH and amount of adsorbent, was evaluated. The results showed that the prepared nanocomposite can be used efficiently for the treatment of tannery wastewater containing heavy metals.