In this work magnetic biosorbent, which consisted of sugarcane bagasse as polymeric matrix with magnetite nanoparticles, was prepared. This magnetic composite has the purpose to remove uranyl ions from aqueous effluents. This magnetic biosorbent have presented superparamagnetic properties. Variables of adsorption process of uranyl ions by magnetic biosorbent in nitric solutions were investigated, such as, time required for the uranium-magnetic bagasse biosorbent equilibrium in the interval from 20–90 min, pH in the intervals from 2–5 and 10, stirring speed from 240–500 rpm and biosorbent dose from 2–25 g L –1 were investigated. Equilibrium isotherm was verified according to the Langmuir and Freundlich adsorption isotherm models.