This paper presents an approach to determine the location of fault in transmission network based on the "waveform matching“ algorithm. The during-fault waveforms resulted from a simulation program of the test system will be compared to the waveforms resulted from a short-circuit calculation program, fed with the suggested fault location and fault resistance, for matching. The search process to find the best waveform match is actually an optimization problem. The genetic algorithm (GA) is introduced to find the optimal solution. This method can offer more accurate results than other known techniques.