Poly(acrylic acid amidoxime) [P(AA-AO)] and poly(maleic acid amidoxime) [P(MA-AO)] resins were prepared by the gamma-radiation-induced copolymerization of acrylonitrile with acrylic acid and maleic acid, respectively. The obtained resins were amidoximated by reaction with hydroxylamine. The prepared resins were used for the removal of methyl violet (MV) dye from aqueous solutions. Batch adsorption studies were made by the measurement of the effects of pH, the amount of adsorbent, the contact time, and the adsorbate concentration. The adsorption isotherm of MV onto P(AA-AO) and P(MA-AO) was determined at 25 C with initial MV dye concentrations of 10-70 mg/L. The equilibrium data were analyzed with the Langmuir and Freundlich isotherm models. The equilibrium process was described well by the Langmuir isotherm model with maximum adsorption capacities of 398.4 and 396.8 mg/L for P(AA-AO) and P(MA-AO), respectively. The kinetics of adsorption of MV onto P(AA-AO) and P(MA-AO) are discussed. The pseudo-second-order kinetic model described the adsorption of MV onto P(AA-AO) and P(MA-AO) very well. (C) 2010 Wiley Periodicals, Inc. J Appl Polyrn Sci 120: 1547-1554, 2011