El expediente previo matrimonial es un elemento esencial de validez del matrimonio celebrado en forma civil o religiosa. La Sentencia del Tribunal Constitucional 194/2014, de 1 de diciembre de 2014, resuelve sobre la reclamacion de una pension de viudedad en el marco de un matrimonio contraido por el rito islamico sin haberse practicado su inscripcion, ni tramitado el pertinente certificado de capacidad matrimonial. Por un lado, es precisa una reflexion critica sobre los requisitos que ha de cumplir en aras a su eficacia el matrimonio celebrado al amparo del art. 7 de la Ley 26/92 del Acuerdo de Cooperacion entre el Estado espanol y la Comision Islamica de Espana, asi como del resto de confesiones religiosas. Por otra, en nuestros dias, la cuestion del certificado de capacidad matrimonial aflora asimismo en multitud de matrimonios donde existe un elemento de extranjeria. Palabras clave: celebracion del matrimonio, rito islamico, expediente previo matrimonial, certificado de capacidad matrimonial, Derecho internacional privado. Abstract: Legal marriages preliminaries are essentials elements in order to de the validity of the marriage celebrated according to the civil or religious ceremony. The Judgement of the Constitutional Court 194/2014, 1th December 2014, resolves an application for a survivor’s pension under a marriage celebrated by the Muslim rite, lacking civil registration and the relevant certificate of legal capacity to marry. On the one hand, there is a need for a critical discussion about the necessary requirements to meet for a valid marriage celebrated under article 7 of the Law 26/92 Agreement of Cooperation between the Spanish State and the Islamic Commission of Spain, as well as the rest of religious faith. On the other hand, today the question of certificate of legal capacity to marry have also emerged in many marriages involving a foreing element. Key words: marriage celebration, Muslim rite, legal marries preliminaries, certificate of legal capacity to marry, Private international law.