Power systems may split into several electrically disconnected islands following large disturbances caused by natural disasters such as hurricanes, storms and the like. Timely and accurate detection as well as identification of islanding is of utmost importance to the system operators in order for the system to be rapidly restored. This paper presents an islanding identification method using state estimation. Island identification is formulated as a multiple simultaneous line parameter error identification problem. This problem was solved by revising a previously developed method and applying it to cases involving synchronized phasor measurements. The method is capable of identifying the new network topology following islanding event. Simulation results obtained from IEEE 14- and 30-bus systems are provided as illustrations of the proposed method.