This paper aims to evaluate the performance of banks in Tunisia from 2011 to 2013. An approach based on relations between fuzzy numbers (BRONF) is used to solve the fuzzy data envelopment analysis (FDEA) model in presence of financial and non financial data. In addition, a methodology is proposed to treat imprecise inputs and outputs. The results show that, in a competitive environment, no-financial inputs and outputs should be taken into account in order to obtain credible and realistic efficiency scores.