The recombination of polycarbonate (PC) chains has been researched as one of the studies on selfrepairing materials. The specimens, which included sodium carbonate and Tri(2,4-di-t-buthylphenyl)phosphate, were treated at 120degreesC in a steam chamber and subsequently at 130degreesC under nitrogen atmosphere. The molecular weight of the specimen with 0.1 ppm of sodium carbonate increased during the subsequent treatment. The same tendency was observed when sodium carbonate was supplementally added to the specimen. In particular, the molecular weight little changed under severe condition when the concentration of sodium carbonate was controlled to be 100 to 1000 ppm. The result showed PC could be used as a self-repairing material. The deterioration is expected to be minimized if the recovery rate is the same as the deterioration rate by applying these self-repairing systems. The tensile strength, the transparency, and the reaction schemes are discussed. (C) 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 920-926, 2004.