Following the 2003 publication of the European Union (EU) Council Recommendations and the 2005-2008 and 2009-2012 EU Drugs Action Plans, increasing attention has been given in EU member states' drug policies to populations that are vulnerable to problem drug use (PDU). Monitoring data reported to the EMCDDA by designated agencies from 30 countries highlight that vulnerable populations tied to institutions (e.g. young drug law offenders, pupils with academic problems, youth in care institutions) receive more attention in policy and intervention provision than vulnerable groups that are hard to reach (e.g. immigrants and homeless youth). The context of vulnerability to PDU in the EU is discussed, including the inadequacy in many member states of alternatives to imprisonment for underage drug law offenders, the difficulty of addressing the needs of ethnic and migrant groups and opportunities for prevention in culturally disadvantaged neighbourhoods. (Contains 1 table and 1 figure.)