Hydrogel of acrylic acid-acrylamide (AA/Am) has been prepared to investigate its efficiency in the adsorption of a toxic cationic methyl blue (MB) dye from synthetic aqueous solutions. Batch conditions of various pH, initial dye concentrations, adsorbent doses, ionic strength and temperatures, respectively have been studied. The optimum conditions of MB dye adsorption were at a contact time of four hours, 1.5 g/l of hydrogel, in an aqueous solution of pH 10, at 40 °C, and the % removal of the dye under these conditions reached about 95%, and the dye adsorption kinetic process has been analyzed using pseudo first and second-order kinetic models. The results presented that the adsorption kinetics of MB dye followed a pseudo second-order model very well. FTIR, SEM and XRD tests have been also conducted to illustrate the properties and characterizations of the prepared hydrogel.