Abstract:? The European Union aims to develop a European criminal justice to combat cross-border crimes of smuggling of migrants and trafficking in human beings. This article focuses its attention on European Community/European Union (EC/EU) law and on two Member States, Italy and the United Kingdom (UK). The findings show that there are diversities and ambiguities in the definition of irregular migration. On the contrary, the EU and Member States should concentrate their efforts on the two crimes of smuggling of migrants and trafficking in human beings rather than criminalising irregular migration.