Microcomposites of polypropylene (PP) and magnetite (Fe3O4) in different concentration were prepared by one-step melt blending of magnetite powders and polypropylene. Morphology of the composites was studied by means of scanning electron microscope (SEM) to investigate magnetite dispersion within the polypropylene matrix. Thermoxidative stability and mechanical properties were investigated, showing improved thermal stability and enhanced stiffness. Magnetic properties characterization showed a ferromagnetic behavior with coercive field of 116 Oe and saturation magnetizations linearly dependent on the content of magnetic phase.