A conductive polymer composition which has a resistivity at 20 °C of at most 1.0 ohm-cm and a PTC anomaly of at least 104 contains at most 64 % by volume of a crystalline polymeric component and at least 36 % by volume of a particulate conductive filler. A preferred conductive filler is carbon black having a DBP number of 60 to 120 cm3/100 g. Compositions of the invention, as well as other conductive polymer compositions, are preferably prepared by a method in which the polymeric component and the filler are blended in a first step at a temperature greater than the melting temperature of the polymer, the mixture is then cooled, and the mixture is then mixed in a second step. The resulting composition has a PTC anomaly that is at least 1.2 times the PTC anomaly of the first mixture.