The application of an external dc electric field E = 5 kV/cm during the annealing of electrodeposited Cu foil at 150-195 degrees C retarded grain growth. The time dependence of the grain size both with and without the field was D = A(o) exp(-Q/RT)t(n) where A(o) = (3.53-4.35) x 10(-5) m s(-1), Q = 11.3-11.6 kJ/mole and n = 0.048-0.052. The field consistently reduced A(o), but had no clear effect on Q and n. Consideration of the grain growth kinetics in terms of the expression dD/dt = M-o exp (-Q(M)/RT)P-q gave Q(M) = Q/n = 233-239 kJ/mole and q = 1/n-1 = 19.1-20.1. Theoretical considerations along with data in the literature on grain boundary migration in Al and Cu suggest that these values of q and Q(M) could reflect the action of impurities. Several possibilities are given for the decrease in A(o) and the corresponding retardation of grain growth by the field. Good accord occurred for a reduction by the field. of the dislocation density contribution to the driving force P. Grain growth data in the literature, along with the present results, are in some accord with both the impurity drag and topology models; hence both should be considered in any analysis of grain growth kinetics.