Nanosized Sb doped SnO 2 (ATO) particles were successfully synthesized. Electrically conducting rubbery composites based on epichlorohydrin rubber (ECO) and two kinds of conductive fillers (SnO 2 and ATO) were prepared by a conventional blending method. The morphology, structure and electrical conductivity of ECO/SnO 2 and ECO/ATO composites were investigated. Results showed that SnO 2 and ATO had great influence on the structure of ECO composite. Besides, the addition of oxide particles enhanced its electrical conductivity significantly. The electrical conductivity of ECO/ATO composite appeared an obvious threshold value with the variation of the loading amount of ATO fillers, whereas the resistivity of ECO filled with SnO 2 decreased monotonically with the increasing SnO 2 . The temperature dependence of resistivity indicated that the ECO/SnO 2 and ECO/ATO composites exhibited a negative temperature coefficient (NTC) effect. Scanning electron microscopy (SEM) was used to investigate the morphological states of oxide fillers in ECO matrix, and specifically continuous networks were observed. POLYM.