Flexible heaters were prepared by extruding platinum-catalyzed silicone rubber (SR) compound with carbon black (CB)/multiwalled carbon nanotube (MWNT) and CB/SnO2-Sb coated titanium dioxide (TiO2). MWNT with average particle length of 20 mu m and acicular shaped TiO2 with average particle length of 1.7 mu m were selected. Thermal aging and mechanical deformation stability were compared for SR/CB, SR/CB/MWNT, and SR/CB/TiO2 composites system. During thermal aging, conductor resistivity decreased because of the toughening effect of SR matrix. When 1 wt % of MWNT and TiO2 were added into SR/CB compound, the deformation stability increased significantly. Thermal reproducibility and voltage stability of the extruded heaters were also investigated by applying AC voltage of 220 V. The heaters containing MWNT exhibited poor thermal reproducibility and voltage stability compared with heater containing TiO2 or unfilled. (C) 2008 Wiley Periodicals, Inc.