Abstract: Trends in demographic development in many countries demonstrate that ethnic migrants in the ensuing years are likely to become one of the more significant target groups that require a specialized approach in dealing with drug and addiction problems. In a more globalised world, migration and cultural diversity are developing in an international context and have a transnational character with far-reaching national implications. This situation poses challenges both for local population and migrants. It is rather difficult for migrants from other cultures to integrate into the new society. Migration becomes an arduous challenge, and not many people can withstand that. In some cases migration aggravates already existing drug and alcohol problems, in others it becomes a trigger to starting drug use. In addition to regular migration, people increasingly move to other countries illegally and become what is termed today “irregular migrants”. In many countries there exists a well-functioning system of social welfare, treatment and rehabilitation for drug users. However, effective system of support to drug users who are ethnic migrants, especially irregular ones, that would take into account their social, psychological and cultural specificities is not in place. But how can we provide services of high quality, if we do not take into account the differences of those who we try to help? Many differences of migrants have sustainable cultural and behavioural patterns: ways of using drugs, attitude towards drug treatment, a choice of treatment modality etc. The diversity of types of migrants, their ethnic origin, various motives for migration, numerous reasons for taking drugs and alcohol – this all serves to emphasize that there is no universal formula in dealing with ethnic groups of drug users.