The Master's thesis describes and analyses the legislation of the on-site inspections conducted by the Czech Office for the Protection of Competition and the European Commission. The competition authorities may investigate business and other premises in order to find evidence proving the violation of competition rules. The on- site inspection or so called dawn raid is a main investigative and the most effective tool of the competition authorities in proceedings concerning the possible breach of competition law. The main aim of this thesis is to provide a detailed description of the relevant legislation and case law, to highlight any legal issues connected with on-site inspections and offer solutions of these issues, and finally to examine guarantees of the fundamental rights of the undertakings during the inspection. The thesis consists of eight chapters. Chapter One and Two are introductory and describe basic terms connected with the competition law. In Chapter Three the thesis deals with the scope of relevant Czech and EU legislation. Chapter Four is concerned with the guarantees of fundamental rights within on-site inspections. This chapter comprehensively describes and analyses relevant decisional practice of the European Court of Human Rights, Czech and EU courts, in which those courts...