The importance of interoperability among computer systems has been progressively increasing over the last years. The tendency of current cataloguing systems is to interchange metadata in XML according to the specific standard required by each user on demand. According to the research literature, it seems that there exist two main approaches in order to tackle this problem: solutions that are based on the use of ontologies and solutions that are based on the creation of specific crosswalks for one-to-one mapping. This paper proposes a hierarchical one-to-one mapping solution for improving semantic interoperability.