ENFighting crime always was a state task, that used as far as possible achievements of science and technology. One of main forms of introducing of achievements of science and technology into processes of revealing, fighting and prevention of crimes is judicial expertise. Being an European Union Member obliges to adjust and harmonize local law with EU law. European Union has specific tools to ensure this. Some Union solutions are obligatory from their adopting, others need to be implemented into local law systems. The article describes changes of lithuanian legislation concerning judicial expertise which are an effect of Union law implementation into the law system of Republic of Lithuania. The article emphasizes EU activity in the aspect of security ensuring including creating of European area of judicial sciences and development of its’ infrastructure. Keywords: judicial expertise, expert activity, implementation of law, European Union, Lithuania.