Copper wires were bombarded with 12-Mev deuterons at low temperatures. The wires were then allowed to anneal isothermally at successive temperatures from -185\ifmmode^\circ\else\textdegree\fi{}C to +167\ifmmode^\circ\else\textdegree\fi{}C. Recovery of the electrical resistivity increase, produced by the bombardment, was observed at all temperatures. The annealing curves obtained for temperatures between -185\ifmmode^\circ\else\textdegree\fi{}C and -60\ifmmode^\circ\else\textdegree\fi{}C were of such a character that only a number of processes with different activation energies could account for them. One-half of the resistivity increase recovered in this range. The activation energies obtained were observed to be proportional to the absolute temperature. A value of 0.44 ev was found near -100\ifmmode^\circ\else\textdegree\fi{}C. Above -60\ifmmode^\circ\else\textdegree\fi{}C the annealing behaved as though it were a single process with a unique activation energy. This process accounted for 25 percent of the increased resistivity and had an energy of 0.68 ev. At room temperature 25 percent of the increase remained, and further anneals to temperatures as high as 167\ifmmode^\circ\else\textdegree\fi{}C produced only an additional 4 percent recovery.Detailed analysis of the data suggests that the single process occurring above -60\ifmmode^\circ\else\textdegree\fi{}C is the result of the annihilation of interstitial atoms and vacancies that are produced by the irradiation. Slight deviations of the recovery rate from that expected of such a second-order process were observed and could be explained as the effect of elastic strains introduced into the lattice by interstitial atoms. The effect of such lattice strains on the rate of vacancy migration was calculated and found to have sufficient magnitude to explain the data. The results also suggested that the low temperature recovery is due to the correlated annihilation of very close interstitial vacancy pairs, the low activation energies being due to large elastic strains in the immediate vicinity of an interstitial. A further result, which can be derived from the activation energy for self-diffusion in copper, is that the energy of formation of a vacancy is 1.39 ev.