As a result of collection, description and ordering of the musical scores of the Eastern Rite Catholic Church in Bulgaria an archive has been created. This archive should give a solid base for further investigations of the cultural and musical traditions of the community. The selection of the classificational principles, being one of the major problems in the AE description, draws on already established archive models in Bulgarian and foreign musicology, such as the works of Christina Japova “The Archive of Dobri Hristov” and the Vatican Film Library, as given in “Manuscripta 2006”. The making of an inventory by means of AE in text format provides conditions for future detailed and serious research work, based on this archive.