Living poly(methyl methacrylate) (PMMA), prepared by the RAFT technique, reacted with maleic anhydride to give succinic anhydride-terminated PMMA (SA-PMMA) in very high yield. The omega-terminal anhydride residues react in high yields with primary alcohols, primary amines and aromatic amines. As examples, SA-PMMA reacted with 1H,1H,2H,2H-perfluorodecylamine to give a polymer containing 5.78% of fluorine; with Disperse Orange 3 to give a dye-labeled PMMA; with 9-hydroxymethylanthracene to give a fluorescently labeled PMMA; with norephedrine to give a polymer with a biologically active end group; and with 4,4'-diaminophenymethane to give amine-ended PMMA. The latter reacted smoothly with fluorescein isocyanate to give a fluorescently labeled PMMA. In these examples the fraction of polymer chains functionalized were in the range 75-95%. Allowing for the fact the starting PMMAs were up to 96% living, these loadings correspond to functionalization yields, for the anhydride addition plus the reaction with the nucleophiles, of 81-99%.