The entity-relationship model (E-R) is applied to the descriptive part of the Spanish Cataloguing Rules with the objective of to detect its strong and weak points with a view to the upgrade of this code, to adapt to the new normative inter-national that is gestating in these moments. After a brief historical context in the make an appointment the key points in the development of the contemporary cata-loguing, the specific objectives are exposed that are sought to get with this study. After explaining the methodology carried out, the main obtained results are pointed out. This section is structured by means of a series of keys questions to those that the cataloguing codes have to make front to adapt to the new means, new publication forms, and new diffusion and access of the information in the digital environment. By way of conclusion, they are picked up a series of recommendations that it should be kept in mind for the development of the new instructions that it take place in a fu-ture.