The book aims at analysing the European Union’s approach towards coexistence of GM crops with conventional and organic agriculture. In the European Union no form of agriculture, whether conventional, organic or GM, should be excluded. Farmers are free to choose the production type they prefer, without being forced to change patterns already established in the area and without spending more resources. First, the study will analyse the necessity and advisability of a regulatory approach to coexistence, by covering the history of European legislations in this field. Subsequently, the analysis will cover the Danish, Hungarian and Portuguese models where the competence for coexistence lies at national level, coming to a brief description of the Italian approach where, on the contrary, the competence for coexistence lies at regional level.