At paper proposes that the patrimonial liability of the Administration is not only based on the fault of the public service as the only title of attribution of liability, as has been accepted in a uniform manner by the jurisprudence, but that it is legally possible that, together with the fault of public service, coexist other imputation titles that establish exceptional liability systems without fault, based on a correct interpretation of article 4° of the General Law of General Bases of the State Administration.