The use of power switches in modern system chips (SOCs) is inevitable as they allow for efficient on-chip static power management. Leakage is today one of the main hurdles in low-power applications. Power switches enable power gating functionality, i.e., one or more parts of the SOC can be powered-off during standby mode leading in this way to savings in the overall SOC?s power consumption. In this paper, we present a circuit and a method to test power switches. The proposed method allows testing of on/off functionality. In case of segmented power switches individual failing segments can be identified as well by using the proposed test strategy. The method requires only a small number of test patterns that are easy to generate. Furthermore, the proposed method is very scalable with the number of power switches and has a very small area-overhead.