Abstract: Conductive polymer having a steeply-sloped positive temperature coefficient (PTC) of resistance with a sharply defined anomaly temperature is provided by selecting a polymer having crystalline structure at room temperature, a glass transition of approximately 13.degree.F. or lower and a narrow molecular weight distribution as measured by a flow ratio of less than 9 or a melting point range of 30.degree.C. or less. The polymer is filled with conductive particles and may include additional additives such as stabilizing agents and flame retardants. The ingredients are mixed, subjected to shearing forces and then formed into the desired configuration. The maximum permissible processing temperature is identified for the specific polymers employed.