The master thesis consists of an analysis of the right to defense and the defender of one's own choice in criminal proceedings and his position in criminal proceedings. At the beginning of the paper, the international legal regulation of this right is analyzed as one of the fundamental human rights. As part of the treatment of international legal regulation, an insight is given into the regulation of the right to veterans of their own choice at the global level, i.e. within the United Nations and at the regional level, i.e. within the Council of Europe and the European Union. Furthermore, the regulation of the institute in question in the Croatian legal system is discussed, and the concept of formal defense is defined and the difference between defenders of their own choice and other types of defenders in criminal proceedings is pointed out. The concept of defender, its characteristics, the method of choosing a defender and the actions he can take in the procedure are elaborated in more detail. Part of the paper refers to the analysis of the judgments of the European Court of Human Rights and the Constitutional Court of the Republic of Croatia as two courts relevant to the protection of fundamental human rights, which includes the law with which this paper deals.