A process for stabilizing a silicon-containing methacrylate having the formula (I): ##STR1## wherein X is Si(OCH.sub.3).sub.3, Si(OCH.sub.3).sub.2 CH.sub.3, Si(OCH.sub.3)(CH.sub.3).sub.2 or Si(CH.sub.3).sub.3 which comprises adding 2,5-di-t-butylbenzoquinone to the silicon-containing methacrylate, whereby polymerization of the silicon-containing methacrylate can be inhibited. As a result, the silicon-containing methacrylate can be stabilized without any trouble in distillation step.