Abstract: A two step process for the production of high impact strength polymer compositions. The process includes reacting an acrylic and a vinyl aromatic with an elastomeric polymer, forming an intermediate reaction product containing acrylic and vinyl aromatic units grafted on to the elastomeric polymer backbone. Additional acrylic and vinyl aromatic are added and a final reaction product suitable for use in molding processes is produced. Preferably, both steps of the process are carried out in aqueous suspension. The product is made up of an insitu mixture of a graft polymer having elastomeric polymer backbone and a random polymer made up of units of vinyl aromatic and acrylic units.