This paper estimates the efficiency of electricity distributors in Brazil and, based on the results obtained, analyzes which factors are related to their inefficiency. To this end, a two-stage DEA analysis is used, in the first stage the DEA method is used to estimate the efficiency of the distributors, and in the second stage regressions are carried out on the efficiency results. It was observed that private distributors are more efficient than public ones, and also that the returns to scale of Brazilian distributors are very diverse.