Poly(methyl methacrylate) (PMMA) was synthesized in different ionic liquids (IL) by free radical polymerization. The average molecular weight and poly-dispersity of the PMMA were measured by gel permeation chromatography. It is found that ILs have effect not only on the molecular weights but also on the stereostructure of PMMA. From the FTIR and NMR analysis, it was confirmed that the chemical structure of PMMA synthesized in ILs was similar to the one obtained in conventional solvents while the stereostructure was influenced by the different IL used. (c) 2006 Wiley Periodicals, Inc.