Utilization of environmentally benign solvents, nontoxic chemicals, and renewable materials are some of the key issues that merit important consideration in a green synthetic strategy. In this work, monodispersed magnetic Fe2O3 nanoparticles have been synthesized by using regenerated cellulose films as sacrificial templates. Transmission electron microscopy (TEM) and scanning electron microscope (SEM) images indicated that the particle size of the nanoparticles was less than 50 nm. The nanoparticles had novel magnetic responsibility at room temperature and could be dispersed in water and kept at stable state for about 3 months. The nanoparticles were prepared directly without a size-selection process, and the synthetic procedure was reproducible. Furthermore, this method was facile and the process was completely green, which made this process amenable to the further development of green nanoparticle synthesis on a large-scale. (C) 2011 Elsevier B.V. All rights reserved.