The [...] paper examines for the first time the impact of the Eastern Enlargement of the European Union on the phenomenon of trafficking and the development of counter-trafficking measures in Estonia, Latvia, and Lithuania. Units of analysis are thirteen actors that are involved in counter-trafficking activities in the Baltic States at both national and international level. The survey has been conducted with two methods: in writing (questionnaire) and in oral (telephone-interviewing). The paper shows how the phenomenon of trafficking has developed in the recent past and how the actors rate the influence of the EU Eastern Enlargement on these changes. Furthermore, it is shown how counter-trafficking activities of diverse actors have been influenced by the Baltic States? membership in the European Union. In this context, it is also looked at the influence of European prostitution discourses on the development of national discourses in the Baltic States. (Abstract of the thesis)