This report has been developed within the remit of the project “EU interoperability with HERA’s IT Platform (EU-HIP)”. EU-HIP is a consortium of 15 European countries, coordinated by Statens Serum Institute (SSI), Denmark. The scope of the project is to support countries to enhance and improve national IT systems in an efficient and coordinated manner, with the objective of obtaining interoperability with the centralised IT platform of the EU Health Emergency Preparedness and Response Authority (HERA). HERA’s IT platform (ATHINA) is currently under development and seeks to gather intelligence on public health surveillance and medical countermeasures (MCM) to support threat assessment and crisis management across Europe. The priority areas are pathogens with high pandemic potential (PHPP), antimicrobial resistance (AMR), and chemical, biological, radiological and nuclear (CBRN) threats, as well as appropriate medical countermeasures, such as medicinal products, medical devices and personal protective equipment (PPE). A baseline activity of the EU-HIP project is to perform a landscape assessment of countries’ IT systems, in relation to the above-mentioned priorities, across all countries involved in the consortium. In addition, in-depth country visits are being performed in a selected number of countries, to gain detailed insights on the countries’ IT systems for health threat detection and assessment. This report presents the findings from the landscape assessment and in-depth country visit in Croatia.