This work describes the preparation and characterization of polyvinylidene fluoride (PVDF)/iron oxide nanocomposites fabricated from monodispersed 6 nm iron oxide nanoparticles in the crystalline form of magnetite (Fe3O4) and polyvinylidene fluoride in a mixed solvent system (THF/DMF) through the solution mixing technique. Structural analysis using high-resolution transmission electron microscopy showed that the 6 nm iron oxide nanoparticles were uniformly distributed in PVDF matrix. The piezoelectric responses of PVDF/iron oxide nanocomposites were extensively increased about five times in magnitude with applied electrical field poling at 35 MV/m. The incorporation of 2 wt% iron oxide nanoparticles into the PVDF matrix improved thermal stability as compared to that of PVDF. This is can be ascribed to the incorporation of inorganic iron oxide nanoparticles to PVDF required more thermal energy for degradation, thus caused a decrease in the degradation rate and an increase in the residual weight for PVDF/iron oxide nanocomposites.