The aim of this work is evaluating and analyzing the performance indicators of business process outsourcing. The criteria influencing the performance of business process outsourcing are indicated through a large literature survey and experts' opinions, and a multi-criteria decision model is thought to be appropriate because of the complexity of the problem. Fuzzy cognitive map methodology is a suitable tool due to the presence of causalities, positive as well as negative directions of relationships among criteria, and the difficulty of expressing the interrelations with crisp numbers. The proposed methodology provides an evaluation for clients to assess their service providers, a selfevaluation for service providers. Hence, this work proposes a mutual assessment.