A simple method for the activation of the Cu(0) wire used as catalyst in single-electron transfer living radical polymerization (SET-LRP) is reported. The surface of Cu(0) stored in air is coated with a layer of Cu2O. It is well established that Cu2O is a less reactive catalyst for SET-LRP than Cu(0). We report here the activation of the Cu(0) wire under nitrogen by the reduction of Cu2O from its surface to Cu(0) by treatment with hydrazine hydrate. The kinetics of SET-LRP of methyl acrylate (MA) catalyzed with activated Cu(0) wire in dimethyl sulfoxide (DMSO) at 25 degrees C demonstrated a dramatic acceleration of the polymerization and the absence of the induction period observed during SET-LRP catalyzed with nonactivated Cu(0) in several laboratories. Exposure of the activated Cu(0) wire to air results in a lower apparent rate constant of propagation because of gradual oxidation of Cu(0) to Cu2O. This dramatic acceleration of SET-LRP is similar to that observed with commercial Cu(0) nanopowder except that the polymerization provides excellent molecular weight evolution, very narrow molecular weight distribution and high polymer chain-end functionality. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 5109-5119, 2010