An ionic liquid, 1-butyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)imide ([C(1)C(4)Im]-NTf2) was used as the polymerization medium for the SG1-mediated free-radical solution copolymerization of methyl methacrylate with a low percentage of styrene, initiated by the BlocBuilder alkoxyamine at 90 degrees C. Control over the polymer molar mass and molar mass distribution was good, slightly better than that obtained in bulk or classical organic solvent solutions for the same system. Compared to the results of nitroxide-mediated polymerizations in ionic liquids previously reported in the literature, the quality of control was significantly better. It seems that the ionic liquid did not influence the activation deactivation mechanism but played a role on the polymerization kinetics only. Indeed, the overall polymerization rate was found to be larger and the final conversion higher, in good agreement with the increase of k(p) and the decrease of k(t), which are key features of free-radical polymerization in ionic liquids.