Sawdust of rubber wood has been subjected to surface modification by treatment with sodium polysulphide. The product exhibits a good adsorption potential for Co(II). The percentage of Co(II) adsorption increases with increase in temperature and decrease in initial Co(II) concentration. Sorbent is effective for the quantitative removal of Co(II) over the pH range 4-10. The applicability of the Lagergren and Freundlich equations for metal removal has been tested at different temperatures and the adsorption has been found to be endothermic. Thermodynamic parameters have also been calculated to predict the nature of adsorption. The spent sorbent can be regenerated by acid and can be reused.