Reproducible and reliable bipolar resistive switching was obtained from Ag/SrTiO3 (STO)/Pt memory cells. The current-voltage characteristic of the Ag/STO/Pt cells with a positive voltage applied to the Pt electrode and the results of X-ray photoelectron spectroscopy imply that the electrochemical reaction and the diffusion of Ag+ ions play a critical role in the resistive switching effect. The temperature dependence of the on-state resistance, combined with the time dependence of the on-and off-state resistances under a constant voltage, provides further evidence that the resistive switching mechanism should be ascribed to the formation and dissolution of the metallic Ag nanofilaments.