The current report provides results from a cross-sectional bio-behavioural study on HIV and related infections and risk behaviours among current IDUs in the capital cities of the three Baltic countries. The first section of the report provides basic information on the three Baltic countries in general, and injecting drug use, HIV and other infections’ epidemiological situations, health care and harm reduction services in more detail. The second section focuses on the methodology and results of the study and the third provides a short discussion and guidance for future action to tackle the HIV epidemic and its consequences among IDUs in Baltic countries.