The present study explores the possibilities of using chitosan-magnetite (CM) nanocomposites for removal of urea in blood serum. The CM nanocomposites, with an average diameter in the range of 12-33 run, were characterized by transmission electron microscopic and selected area electron diffraction analysis. The particles demonstrate fair ability to remove urea in human blood serum. The maximum removal efficiency was nearly 26%, when 200 mg of CM nanocomposites were allowed to agitate with 25 mL of urea solution of concentration 100 mg/dL. The CM nanocomposites could be easily removed by applying moderate magnetic field. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 3106-3109, 2009