Trafficking in human beings is a highly profitable transnational organized crime activity that is difficult to eradicate. It makes an impact on the lives and safety of many people around the world, including the citizens of the European Union. This paper deals with trafficking in human beings for the purpose of prostitution because sexual exploitation is recognized as the most common form of exploitation of the victims of trafficking. This paper researches the relevant EU legislation on trafficking in human beings, including the EU Directives, the UN Convention and the Council of Europe Convention. It also reviews the work of FRONTEX and EUROPOL as European Union agencies acting to counteract phenomenon of trafficking. Finally, three models of legal regulation of prostitution which are present in three EU member states are being considered: abolitionist model in Sweden, legalization model in the Netherlands and prohibitionist model in Croatia. The aim of this paper is to find out how these models affect the visibility of trafficking for the purpose of prostitution, a question to which it is difficult to offer a clear answer. That is due to the fact that the complete scope of trafficking in human beings is impossible to mesure due to its illegal character and the difficulty of creating consistent and high quality worldwide databases.