The purpose of controlled vocabularies is to organize information and to provide terminology to catalogue and retrieve information in information systems. Vocabularies provide definitions and scope notes, which is especially important in the field of cultural heritage, capturing the richness of meanings and relationships between terms. Therefore, they are important tools for data integrity control and providing reliable search and retrieval, and also essential educational resources. Currently, there are only two controlled vocabularies in the Croatian language related to the field of cultural heritage, primarily museum collections and the protection of cultural monuments: 1) the Classification of museum and gallery objects, 2) the Thesaurus of monument types. They overlap to some extent, but also differ according to the levels of specificity, exhaustivity and structure. As an initial method of vocabulary reconciliation, mapping based on Simple Knowledge Organization System (SKOS) mapping properties is used. This paper aims to examine the possibilities and challenges of vocabulary reconciliation and to provide guidelines for the future use of these valuable terminological resources, to improve the users' access to cultural heritage. Additional mapping of both terminologies to the Art & Architecture Thesaurus will ensure interoperability in the global linked open data environment and provide a multilingual context.