The collection management system (CMS) is a key tool for an institution. It provides numerous functions in cataloging and managing a collection, but is also the source of data that underpins research. It is a large investment for an institution and it must be supported over many years, and managed through its lifespan, until inevitable data must be migrated into a new system. Currently, there are an enormous variety of systems in use across Europe. Some are as basic as spreadsheets, but others are complex, relational databases tailor made for the needs of a single institution. These systems differ in their underlying data model for specimens and in the vocabulary they use, which makes interoperability between systems difficult. The planned DiSSCo infrastructure envisages two-way interoperability of data between a central datastore and collection management systems at numerous institutions. To achieve this goal will require considerable harmonization between these systems. In this report we make recommendations to curators, managers and developers of collection management systems with the aim of improving interoperability. We also take a look at the suitability of today’s data standards, in particular Darwin Core, to support the planned DiSSCo infrastructure. Our findings are based on surveys into collection management systems and their qualities, as well as interviews with system managers and analyses of published data from different systems. Ideally, observations of biodiversity could flow seamlessly between collection management systems, aggregators and researchers, but currently we are far from that ideal.