In this study, nanoscale iron particles were synthesized using the microemulsion method and the properties were compared with the particles produced by the solution method. The nanoparticles were characterized by using the transmission electron microscope (TEM) and powder X-ray diffraction (XRD). The water-in-oil (w/o) microemulsion system was made up of n-octane, cetyltrimethyl-ammonium bromide (CTAB), butanol and water, and was characterized by measuring the conductivity of the solution and interfacial tension between the surfactant solution and the n-octane. The conductivity of the microemulsion system increased from about 10 @ms cm^-^1 to over thousands of @ms cm^-^1 with the addition of water. Interfacial tension between the n-octane and the CTAB aqueous solution was reduced to less than 6 dyn cm^-^1 with the addition of butanol, a co-surfactant used in this study. The average diameter of syn