The restriction of the right to defense as a definite violation of the law

The right of defense takes an essential place in reaching the material truth, which is primariy purpose of criminal justice law. Under the rule of law, material truth can only be achieved through a fair trial. The right to defense is a component of the right to fair trial, which is adopted by the European Convention on Human Rights and regulated by the Constitution. To fulfill the right of defense properly, only legal regulations are not suffiicient; enabling to use the right should also be provided. Within this framework, the restriction of the right to defense in the criminal procedure law is regulated as the absolute ground for violating. In this thesis, firstly, the definitionof the right of defense, its history, its relationship, with the principles of the procedure law, and its place in the right of fair trial are studied. Then, within the scope of the judgements of ECHTHR and the Court of Cassation, the cases of restriction of the right to defense, which leads to a definite violation of the law, are discussed in detail. Key Words: Criminal Procedure Law, Right to a Fair Trial, Right of Defense, Restriction of Right to Defense.