This article confronts the relevance of the confiance principle in different legal systems, trying to describe its position in contemporary constitutional and administrative law, on the basis of a review of a certain number of legal systems, with special reference to the case law of the respective constitutional/supreme courts. Apparently one of the possible provisional conclusions is that a certain amount of convergence does exist, independently of any influence, in Europe, by the jurisprudence of the Luxembourg Court. Some systems ofthe jurisprudence, however, rely on old rules, adapted to the new needs, while others keep on elaborating more and more sophisticated analytical rules mainly through the work of the courts.