Crosslinked amphoteric starch with carboxymethyl and quaternary ammonium groups is investigated as an adsorbent for removal of both acid and basic dyes in solution. Acid Light Yellow 2G, Acid Red G. Methyl Green and Methyl Violet were used to study the adsorption behaviors under various parameters such as pH, dose of amphoteric starches, initial dye concentration, adsorption time and adsorption temperature. At the preset pH value, the relationship between adsorption amount and the initial dye concentrations is given. The adsorption isotherm is discussed by modeling Langmuir and Freundlich isotherm. The kinetic study shows that the pseLido-second-order model fits the experimental data better. Also, the themiodynaillic parameters are shown. (c) 2006 Elsevier B.V. All rights reserved.