This paper presents some research results on the synthesis of polyaniline composites with Ba ferrite for radar absorbing purpose. Reactions were performed by in-situ method, resulting hybrid materials that have both electric and magnetic properties. Their conductivity depends on the polyaniline and ferrite contents. In the best samples, conductivity and magnetic is in good combination. For examples ES-FR28 (cr = 67.55 x 10 exponent -3 S/cm, Ms = 19.5 emu/g) and ES-FR65 (cr = 48.9xlO.3 S/cm, Ms = 31 emu/g). It was prepared radar absorbing materials by mixing composite of polyaniline/ferrite in polyurethane resin (the ratio of polyurethane resin:composite was 1:1 by weight). The RAM (radar absorbing materials) samples have thickness of 1.0 mm
1.5 mm and 2.0 mm. Absorption measured results are quite well with samples containing ES-FR28 and ES-FR65 (samples SPFI.3: -8dB to -24 dB and SPF2.3: -6 dB to -16 dB in the frequency range of 8-12 GHz. The research results show that with their special properties, the composite system materials of polyaniline and ferrite can be applied in manufacturing radar absorbing materials.