In this paper we present the results of a research project promoted by Italian Ministry of Labour devoted to assign a formal certify to Italian private firms who respect Equal Opportunities (EO) between man and woman. The research project has been implemented in the framework of the 2007 European Year of Equal Opportunities for All and has been co-financed by the European Commission. Italian Ministry made a public call, to choose a sample of private firms. The sample was formed by: 14 joint-stock companies, 2 Ltds, 3 cooperatives Ltd, 10 social cooperatives and 5 others form of enterprise. The group of researchers involved is makes by sociologists, mathematicians and economists. The project started in June 2007 when the experts set up the self-assessment questionnaire. The test was carried out from November 2007 until February 2008. The selected firms filled in the self-assessment questionnaires and the sociologists conducted in-depth interviews to the relevant union representatives. A Fuzzy Expert System (FES) is used. The scope for using FES is connected not only to the multidimensional nature of EO and to the need of providing a synthetic indicator of firm's EO without losing the its complexity, but even with the composite group of experts involved. The presence of sociologists, economists trade unions members, not used to a mathematics language, carried us to propose an instrument more user friendly like a FES.