A method has been developed which provides very pure alkyl methacrylate monomers for anionic polymerization. This method takes advantage of the chemistry of trialkylaluminum compounds-their reactivity with alcohols and moisture, and their complex formation with methacrylic esters which facilitates titration of impurities. When coupled with previously known polymerization techniques, this purification methodology allows for both the synthesis of narrow distribution poly(alkyl methacrylates) of controlled and predictable molecular weight and for the utilization of a wide variety of methacrylate monomers. The procedure described herein should be equally applicable to group transfer polymerization. © 1986 Springer-Verlag.