A SiC-based material was synthesized from polyvinylsilane (PVS) by pyrolysis at 1400 K in Ar gas atmosphere. In the ceramization process of PVS, several kinds of gases such as hydrogen, silanes, and hydrocarbons were evolved in the temperature range from 500 to 800 K. The total ceramic yield from PVS was about 36%. PVS was heat-treated using several temperature programmes by reflux heat treatment with a view to increase the ceramic yield. The total ceramic yield increased to 59% by the reflux heat treatment at 600 K. The apparent SiC crystallite size and the atomic ratio of carbon to silicon (C/Si) of the SiC-based material obtained by pyrolysis at 1400 K were almost the same for the PVS reflux-treated and the PVS not heat-treated; an apparent SiC crystallite size of about 2.4 nm, and C/Si of about 1.5. (C) 2003 Kluwer Academic Publishers.