Activated carbons of high adsorbents properties for adsorption of chromium species from aqueous solution and Tannery effluents were prepared from coconut shells by means of chemical activation using as activating agents the KOH and ZnCL2, in atmosphere of N2(g) and CO2(g), respectively. It was found that the adsorption capacity of the produced activated carbons are significantly higher than that of the commercial one that was tested. Based on the results obtained from a variety of characterization methods, it has been determined the presence of functional organic groups, phenols and carbonyls, which are responsible for the activated carbons surface charge and it favored the chromium species adsorption, zeta potential measurements helped to explain the metal adsorption in terms of electrostatic attraction-repulsion behavior of the activated carbon surface and cations of Cr(III) and oxyanions of Cr(VI), respectively. It was observed that the activated carbons CK12 and CZ32 displayed the biggest adsorbents properties, it was adsorbed approximately 721.38 mg of chromium with the CK12, 534.43 mg with the CZ32, and only 274.02 mg with the commercial carbon (CC), by gram of activated carbon, respectively, at pH 4.45 from Tannery effluents. © 2006 Sociedad Chilena de Química.