Ethylene-propylene and acrylnitrile-butadiene rubbers were filled with micro and nano-sized Fe3O4 and carbonyl Fe powders in presence of surfactants or a ionic lig. and cured at 160 degrees C and 15 MPa for 30 min to produce vulcanizates with magnetic and magnetorheolog. properties. Use of the surfactants resulted in increasing the degree of filler dispersion. Magnetization intensity and remanence of the rubbers increased with increasing content of Fe3O4. The rubber vulcanizates showed also good mech. properties (tensile strength, elongation at break) and high cross-linking d.