Monodisperse FePt 3 nanoparticles have been prepared using organic precursor of Fe (Fe(acac 3 )) and inorganic precursor of Pt (PtCl 2 ) by adopting hot injection methods using polyol process. By changing the concentration of precursors, reducing agent and surfactants, we examine different reaction products e.g. different phases of Fe-Pt and their magnetic behaviors. The use of excess surfactant and reducing agents was found to effect the nucleation and growth of the Fe-Pt nanoparticle formation. The Pt rich phases of Fe-Pt show very good electro-active response toward redox reaction of ferro-ferri couple electrolyte which was analyzed using cyclic-voltammetry. © 2015 AIP Publishing LLC.