Electrically conductive polymer composites based on high-density polyethylene and carbon black are obtained. It is shown that polymer composites possess a positive temperature coefficient of electrical resistance. The amount of carbon black required to form electrically conductive paths in a polymer matrix is determined. Dependence of physico-mechanical and rheological characteristics of composites on the content of carbon black is revealed. The concentration interval of carbon black is determined, in which the optimal combination of physico-mechanical, rheological and electrophysical properties of composites.