Defining regulatory default targets is an extremely important issue for electricity distributors, the regulatory agency and all consumers, as it has a strong impact on energy tariffs. Finding a methodology that is easy to implement and that simultaneously meets the needs of everyone involved is a major challenge. This dissertation proposes to test the fuzzy inference methodology, as proposed by ZADEH (1965), with a view to proposing a model for the definition of regulatory energy default targets. In Brazil, the current methodology proposed by ANEEL for the definition of regulatory default targets is linked to the methodology of non-technical losses, which, in turn, has been the target of criticism by the distributors and the academic environment. Thus, an independent methodology for defining regulatory default targets tends to benefit all agents involved. The fuzzy Inference methodology brought direct results, which were very close to those obtained by the ANEEL methodology. The results of using fuzzy inference to achieve the regulatory goals of default showed that it is possible to persist in this path, since the proposed methodology is detached from the non-technical losses methodology, maintaining the principles of regulation by incentive and capturing the heterogeneity of the several concession areas.