The studies and research undertaken reached almost unanimously the conclusion that the greatest threat to the internal security of all world's states, including the member states of The European Union, is contemporary terrorism. In this paperwork we examined in general the current trends of improving the complex activity of judicial cooperation in criminal matters in the European Union, in terms of criminality's forms of manifestation and of european applicable laws. The paperwork is a continuation of the research undertaken in the field of judicial cooperation inside the European Union, as a concrete and more efficient way of preventing and fighting against terrorism. The research may be useful tot academics, students, practitioners as well as to the european legislator, who should permanently adapt the legislation, in relation to the new methods used by the members of the terrorist groups. The essential contribution of this study limits itself to examinig the current forms of judicial cooperation in criminal matters founded by the addopted european normative acts, as well as the proposals for modifying and completing, proposals ment to contribute to the more efficient prevention and fight against terrorism inside the European Union.