Silicon-containing epoxy resins were prepared from diglycidyloxymethylphenyl silane (DGMPS) and diglycidylether of bisphenol A (DGEBA) by crosslinking with 4,4'-diaminodiphenylmethane (DDM). Several DGMPS/DGEBA molar ratios were used to obtain materials with different silicon contents. Their thermal, dynamo-mechanical, and flame-retardant properties were evaluated and related to the silicon content. The weight loss rate of the silicon-containing resins is lower than that of the silicon free resin. Char yields under nitrogen and air atmospheres increase with the silicon content. The LOI (limited oxygen index) values increased from 24 for a standard commercial resin to 36 for silicon-containing resins, demonstrating improved flame retardancy. (c) 2006 Wiley Periodicals, Inc.