The degradation of the efficiency of electricity distribution networks is one of the major problems suffered by most network managers, it is mainly due to the phenomenon of electricity fraud causing huge losses for several countries, especially those still developing.The objective of the work presented in this paper is to improve the efficiency of the electricity distribution network, and to identify and justify the existence of electricity fraud in some areas. Those operations are based on the analysis of consumption data recorded by smart meters installed in MV/LV substations and supervised using a remote meter reading system. Without changing the conventional meters installed at the customers, the methodology followed starts with the sectorization of the electrical network, in order to determine the limits feeding each zone. Then, it calculates the efficiencies, and makes a detailed audit of the efficiency on each zone, by decreasing the technical losses and the non-technical losses due to the defects of the meters. Finally, it analyzes the data of the smart meters. Real studies, that have been carried out on electricity distribution networks during two years, demonstrates the effectiveness of the proposed approach.