The room temperature resistivity and the magnetoresistivity of AuCu have been investigated as a function of the degree of order. Measurements were made first of all on samples quenched to room temperature after reaching equilibrium at temperatures below the Curie point. In addition measurements were made on samples which were first disordered by quenching from a temperature above the Curie point, were then annealed for various lengths of time at 265°C, and were finally quenched to room temperature. The coefficient of magnetoresistivity equals 1.8×10−12and 6×10−14gauss−2, respectively, for the completely ordered and completely disordered alloy. The equilibrium curve for the magnetoresistivity shows a minimum at 365°C and a pronounced maximum at 388°C which is close to the transition temperature for the phase change of AuCu I to AuCu II. No such extremes in the value of the coefficient of magnetoresistivity occur during the annealing of a thermally disordered sample.