The right-duty of professional secrecy is one of the fundamental principles of legal ethics. This principle mainly obliges the lawyer not to reveal the confidential data of his clients, especially in the criminal field. Internationally recognized in the world of Law, this figure in our country is regulated in various regulations, among which we can first highlight the Spanish Constitution of 1978 (hereinafter, CE), which recognizes the right of the lawyer not to testify against his defendant. Similarly, the Organic Law of the Judiciary (hereinafter, LOPJ), the Penal Code (hereinafter, CP) of 1995, and especially the General Statute of Spanish Lawyers (hereinafter, EGAE) and the Code of Ethics of the Spanish Lawyers (hereinafter, CDAE).Howev...