Biosorption is an emerging technique for water treatment utilizing abundantly available biomaterials.The potential feasibility of magnetic peanut hulls particle for removal of cationic dye (methylene blue) from aqueous solution was investigated. The effects of various experimental parameters were examined and optimal experimental conditions were decided. Characterization of biosorbent was carried out by Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analyzer. FT-IR analysis showedthe presence of hydroxyl, carbonyl and carboxyl groups which can involve in the biosorption process. The results in this study indicated that peanut hull was an attractive candidate for removing cationic dyes from dye wastewater. Different kinetic and equilibrium models were applied to the experimental data. Tempkin model was the most fitted isotherm as R2= 0.963. While the resulting data for the different parameters studied was suitable to be pseudo second order.