In our continued work with the ultrasonically initiated free radical polymerization of olefins, we have included experiments for the emulsions polymerization of methyl methacrylate. We have shown that polymerization can be initiated in emulsions containing monomer and a special initiator with intense ultrasound. The weight average molecular weight of the Poly(methyl methacrylate) varies from 1,100, 000 to 1,700,000 g/mol and the conversion for the polymerization is up to 70%. Variations of the polymerization rate with time vs the amount of initiator are explained by a simple reaction mechanism.