Epoxy-melamine hybrid resins were obtained from in situ polymerization of siliconized (SE500) and phosphorylated (PE690) epoxy resins with hexakis(methoxymethyl)melamine (HMMM). The hybrid resins having HMMM contents less than 15 wt % exhibited high transparency and homogeneity. The compatibilities between SE500 and melamine as well as that between PE690 and melamine were poor than the compatibility between general bisphenol-A epoxy and melamine. Incorporation of HMMM altered the degradation mechanisms and enhanced the thermal stability of the epoxy resins, especially for PE690 based resins. Excellent flame retardant property was observed with the hybrid resins because of the Si-N and P-N synergisms of flame retardation. (c) 2006 Wiley Periodicals, Inc.