Spherical uniform-sized iron ferrite nanoparticles were synthesized by adding a disaccharide and seed ferrite crystals into an aqueous reaction solution. The average size range 50-150nm was controlled by choosing one out of five disaccharides and by changing the amount of the seed crystals. The particles had a saturation magnetization and a crystalline structure which are similar to those of intermediate Fe(3)O(4)-gamma-Fe(2)O(3). When coated with citrate, the particles with nearly 100nm diameter were stably suspended in water for 2 days. These novel particles will be utilized as magnetic carriers in biomedical applications. (C) 2009 Elsevier B.V. All rights reserved.