This paper describes the influence of an external continuous magnetic field on the radical bulk polymerization of methyl, ethyl and butyl methacrylates. The variation in the effect of the field on the ester’s alkylic substituent length is described. The processes were compared with the classical bulk method. Some properties of the synthesized poly(methyl methacrylate), poly(ethyl methacrylate) and poly(butyl methacrylate) are also presented.