Four systems of conductive filler/polyvinylidene fluoride (PVDF) composites were prepared. Abnormal electrical behaviors as functions of temperature and microstructure were analyzed. Results show the carbon black (CB)/PVDF composites present a lower percolation threshold than other metallic filler/PVDF composites. The crystallinity of PVDF is diminished in the order of fillers, CB, Ni, Zn and W. The Ni/PVDF composites exhibit the maximum positive temperature coefficient intensity, whereas the transition temperature is independent of the kind of fillers. The non-uniform distribution of fillers is observed since they aggregate in amorphous regions of PVDF and form a network of conductive chains. (c) 2007 Elsevier B.V. All rights reserved.