Carbon black-filled high-density polyethylene (HDPE)/ethylene ethylacrylate copolymer (EEA) blends were prepared and the effect of crosslinking of the blends on the positive temperature coefficient (PTC) stability was investigated. By irradiation- and silane-crosslinking methods, crosslinked composites with various degrees of crosslinking were obtained. Crosslinking of the matrix polymer led to the disappearance of the negative temperature coefficient (NTC) phenomenon. Also, the PTC intensity increased with an increasing degree of crosslinking. The PTC stability of silane-crosslinked samples was notably improved at heat cycles of 140degreesC. This was sufficiently improved by both the silane- and radiation-crosslinking methods when they were treated at 85degreesC. Therefore, the limiting temperature of self-regulating heat is about 85degreesC. Both radiation- and silane-crosslinked samples are thought to be of use to the industry.