The paper presents a new method based on the Electromagnetic Time-Reversal (EMTR) for locating faults in power systems. The applicability of the EMTR to electromagnetic transients associated with traveling waves in transmission lines originated by the fault is theoretically demonstrated. A new fault location technique is then proposed and illustrated for a simple case of a singleconductor transmission line, for which the performance of the proposed technique in terms of location accuracy is discussed. The use of the EMTR technique appears to be particularly promising for locating faults in passive and active electrical distribution networks in view of their radial structure.