This article reports the effect of crosslinking by gamma-ray irradiation on the morphology, electrical properties, and hardness of poly(vinyl chloride)/graphite composite. A comparison of the scanning electron micrographs of the composites, before and after irradiation, showed that the filler particles were broken into pieces and distributed homogenously as a result of irradiation. The data of electrical conductivity versus graphite content was found to be consistent with the percolation model. A significant increase in the conductivity of composite was observed on the crosslinking of the polymer in consequence of irradiation. The data are correlated with the morphological changes. The study of electrical resistivity as a function of temperature revealed that the negative temperature coefficient of resistivity effect is considerably suppressed after irradiation. These results are explained on the basis of morphological changes in the composites after gamma-ray irradiation. POLYM. ENG. SCI., 49:1136-1141, 2009. (C) 2009 Society of Plastics Engineers