The defender in the criminal trial has an important role and is required by law, to undertake everything and anything that could be in favor of the accused. The main and active defense in the criminal trial does not prevent, but on the contrary it contributes to the fight against crime, helping to remove errors in the examination of criminal cases, to comply with the defense conditions and legitimate interests through means provided by law. In a state subject to rule of law the role and importance of the lawyer is always increasing, which is dictated by the need to change the socio-political conditions, in which a stronger emphasis is put on the observance of human rights and fundamental freedoms. Also, the lawyer having a positive role as an advisor for the client, providing assistance within the criminal trial to suspect, accused or injured party in performing its duties, prevents violations of rights by judicial bodies.