In this paper we review three routes of synthesis of nanoparticles of magnetite (Fe3O4) functionalized to be used to transport drugs. These non- toxic particles, are undoubtedly one of the major responsible for the advance in medical treatment against tumors, targeted drug delivery, immobilization of enzymes, RNA and DNA purification, disease diagnosis using magnetic resonance imaging, dial stem cells, etc. For application the particles must be coated with a biologically active material. Thus magnetite nanoparticles were synthesized by chemical coprecipitation method using various aqueous chemical solutions of FeCl2.4H2O, FeCl3. 6H2O and FeSO4.7H2O mixing in certain proportions. These mixtures were precipitated with NaOH and NH4OH. The surface was treated with an aqueous solution of Fe (NO3)3.9H2O to obtain magnetite nanoparticles with electric double layer. The functionalization was car...