Permalloy NiFe/Si 3 N 4 nanocomposite layers were electroplated on a copper substrate. The volume fraction of nano-sized Si 3 N 4 particles in NiFe matrix was controlled by the addition of various percentages of Si 3 N 4 particles in the NiFe electrolyte. The nanocomposite layers of up to 400 μm were analyzed by a scanning electron microscopy (SEM). Microhardness test was performed. With nano-sized Si 3 N 4 particles in the NiFe matrix, the microhardness of NiFe was improved. The samples were then annealed at 800 o C for about 20 h. The microhardness declined more with more Si 3 N 4 particles in the NiFe matrix. The analysis result from energy dispersive spectrometer (EDS) in the SEM showed that the hardness declination could be caused by the segregation of Si 3 N 4 in the NiFe matrix. Finally, this paper presents nanocomposite micromolds fabricated by electroplating onto polymer molds that were fabricated by micro-stereolithgraphy.