Determining technical losses in an electrical systems is highly complex due to the large amount of information required for its evaluation. One solution to this problem is the evaluation of losses using an artificial neural network. In this work, a modeling was carried out using artificial neural network to evaluate the technical losses in subtransmission electrical networks, which considers the effective length of the circuits, the maximum apparent and active power, the resistance in the conductors and the number of clients connected to said circuit. The simulation results established a mean square error of 0.0028 and correlation coefficent between the variables involved of 0.980. The proposed artificial neural network model resulting satisfactory for evaluating technical losses in subtransmission electrical networks.