It is known that Pt/Pr0.7Ca0.3MnO3 (PCMO)/Pt structures show no hysteresis loops in current-voltage curves due to the symmetric top and bottom interfaces. Here, we prepared an asymmetric memory device using bi-layer PCMO thin films with different oxygen content. The repeatable and stable resistive switching is observed. The excellent resistive switching characteristics such as a large R-HRS/R-LRS (where HRS is the high resistance state and LRS is the low resistance state) ratio ( similar to 1000), sweeping endurance ( > 100), and long retention time ( > 10(5) s) can be obtained using a bipolar operation mode. It is suggested that the switching process can be elucidated to the formation and rupture of localized conductive filament along with the migration of oxygen ions. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3505098] All rights reserved.