The correct application of the Communitarian Law produced by an International Integration Organization implies that member States have to make political and legal internal reforms. However, those obligations are not always undertaken by the States and, therefore, the goals of integration process can not be reached. As this year 2005 is very crucial for the conformation of the Andean Common Market, it is quite important the study of the different mechanisms of application of the Communitarian Law within the member states and the comparison of them with those of the successful European Union experience.