A novel method for the functionalization of vinyl polymers prepared by nitroxide-mediated living free radical procedures is reported. This strategy is based on the controlled monoaddition of maleic anhydride and maleimide derivatives to the alkoxyamine chain end followed by elimination of the mediating nitroxide radical. This allows the introduction of a wide variety of functional groups with high efficiency, while at the same time permitting the alkoxyamine functional group to be removed and the thermal stability of the polymer chain to be increased.