The adsorption of toxic malachite green from aqueous effluents by sugar factory's waste ash was studies in a batch system. The effects of initial dye concentration, kinetic and isotherm behaviors, pH and contact time were investigated. The waste ash showed a high dye removal from an initial dye concentration of 25 mg/L at pH 8 and 303 degrees K. Equilibrium data were well fitted by Langmuir model. The rate of sorption was adjusted to a pseudo second order kinetic model. Adsorption thermodynamic was also studied. The thermodynamic study of malachite green and waste ash was exothermic. The Malachite green can be removed by sugar factory's waste ash from aquatic media.