Cobalt ferrite (CoFe2O4) is a soft magnetic material that can be used as fillers in polypropylene. This magnetic polymer composite is studied for its electromagnetic wave absorbing property. To synthesize CoFe2O4 by the polyvinyl alcohol (PVA) sol-gel method, PVA powder was dissolve in distilled water with 5%, 10% and 15% weight per volume. The solution was stirred and regulated at temperature between 60-80°C until turning into PVA gel. Fe and Co powder of atomic ratio 2:1 were then added to the PVA gel with the metal weight per gel volume 1:6, 1:10 and 1: 12. After sintering at 800°C, phases of the synthesized powder were identified by X-ray diffraction (XRD). Magnetic properties of CoFe2O4 were characterized in order to select the appropriate synthesis condition for electromagnetic wave absorbers.