Several carbon blacks with surface areas from 105 to 1353 m(2)/g were used to produce composites through melt compounding with a high-density polyethylene matrix. The electrical behavior of the obtained composites was investigated by the measurement of their resistivity as a function of the carbon black content and type at various temperatures and times during isothermal annealing treatments. The percolation threshold markedly decreased as the carbon black surface area increased, reaching a minimum value of 1.8 vol % for the carbon black with a surface area of 1353 m2/g. The resistivity passed through a maximum as the test temperature increased. Moreover, the analysis of the experimental data evidenced that the host high-density polyethylene matrix and the conductive carbon black network rearranged during the isothermal thermal treatments, causing a resistivity decrease. This rearrangement became less and less important as the carbon black surface area increased. (C) 2007 Wiley Periodicals, Inc.