Is there effective protection against possible discrimination in the disengagement of the union leaders hired on a fixed term? This question leads us to the following question: Is there any violation in the right to organize when the employment relationship with a worker (union leader) is terminated due to the expiration of the time agreed in the contract, without the need for prior judicial qualification? These concerns highlight the contradiction between internal regulations and the interpretation made by the judges of the republic in jurisprudence, as well as the development of lnternational Labor Standards, especially those that deal with Labor Human Rights and are part of the Constitutionality block. From there, it is necessary to harmonize jurisprudence and internal regulations that protect union leaders hired on a fixed term with constitutional principles and International Labor Standards, so that the requirement of prior judicial qualification becomes essential when An employer intends to terminate or not renew the employment relationship he has with a paid and linked worker through a fixed term contract, in order to determine whether or not there was discrimination in termination or non-renewal of the contract.