In this research, composites of polypropylene (PP) and a relatively small concentrations of iron ferrite (Fe3O4) nanopowder equal to 2, 5 and 10 wt.% have been made. An methacrylate monomer 2,2’-bis-[4-(2-methylprop-2-enoyloxy)phenyl]-propane (BAD) was added at a small amount (3 wt.%) to part of the composites during the thermoplastic mixing. The BAD has been used as a compatibilizing agent on the phase interaction between the filler and the matrix of polypropylene. It has been found that composites have adjustable mechanical, structural and magnetic properties dependent on the content of magnetic filler. Increase of concentration of ferrite particles affects a notable increase of elastic modulus and reduces the deformability in comparison to pure polypropylene, whereas the modification with BAD has mainly a plasticizing effect, affecting a small decrease on stiffness but a notable increase of strain at break. An important role of Fe3O4 adhesion in polymer matrix and interphase effects on the changes of crystallinity and magnetic properties has been found.