This publication sheds light into the situation of drug users among criminal justice populations and corresponding health care responses in ten countries in Eastern and Southeastern Europe: Albania, Bosnia-Herzegovina, Georgia, Kosovo*, Macedonia, Moldova, Montenegro, Russia, Serbia, and Ukraine. Prisons differ across different countries, as do prisoner populations. In some of the countries in the study there is an almost complete unavailability of effective drug dependence treatment (e.g. Opiate Agonist Treatment), or the potential of these treatment has not been exploited yet to its full. But also models of good practice exist in a few of the researched countries. The publication is a product of the Pompidou Group of the Council of Europe project “Improving Drug Treatment Systems in prisons” which was financed by Luxembourg.