This thesis aims, firstly to study the organization, powers and functioning of the Court of Justice of the European Community (ECJ) in the second case law emanating from the same criteria, especially in rulings on rights agriculture and how they influence the legal community, to end with the ending value is the case as a possible source of Community law. Divided into eight titles, consists mainly of two parts. The first deals with general issues such as a brief review of key institutions of the European Union, the accession of Spain to the present and future of the Common Agricultural Policy and the study of the ECJ as an institution and the basic resources that known. The second part is the compilation of the most famous sentences handed down by the ECJ, classified into two groups. The first attorney general interpretation based on the general principles of Community law, as interesting as the new concept of property rights, or the notion of consumers and the second group to discuss the sentences for four CMO: Fats, came, dairy, fruits and vegetables. It concludes with the assertion that the case law emanating from the ECJ, although not a source of Community law, it has the function of applying the same supplement, interpret or revoke its mandatory sources (regulations, directives and decisions).