Magnetic nanoparticles were prepared from gum arabic (GA), 2-hydroxyethylmethacrylate (HEMA) copolymer hydrogel using gamma irradiation. The factors affecting on the preparation of (GA/HEMA) copolymer hydrogel and the magnetic nanocomposite of (GA/HEMA)-(Fe3O4) such as irradiation dose, copolymer composition, copolymer concentration and magnetite concentration were investigated. The swelling property of the prepared hydrogels was studied and the results showed that the swelling percent increases with increasing PH and reaching equilibrium swelling at 6 h. The obtained hydrogel and its magnetic nanocoposites were characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Scanning electron microscopy (SEM) and Transmission electron microscope (TEM). The presence of Fe3O4 inside the GA/HEMA-Fe3O4 nanocomposites was confirmed by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). Magnetic properties were characterized by Vibrating sample magnetometer (VSM). Finally, the drug loading and in vitro release properties of the (GA/HEMA) copolymer hydrogel and its magnetic nanocomposites were also evaluated using endoxan as an anticancer drug model. The results showed that, the optimum endoxan drug release was 97% from (GA/HEMA)-(Fe3O4) nanocomposite during 210 min. Thus, (GA/HEMA)-(Fe3O4) nanocomposite could be used for localized drug delivery for endoxan drug in neutral environment of the intestine.