The submitted diploma thesis deals with sexual offences and their prevention. At the beginning of the thesis, a theoretical basis and a historical overview of the subject are mentioned. The topic is enlarged on various aproaches to ethics and morals in history. Subsequently a legal regulation of these criminal offencesis descibed, not onlythe Czech criminal law, but also the international law and EU legislation. A significant attention is given to the analysis of the elements of sexual crimes, as well as to a statistical data analysis and suggested preventi on measures. The thesis also gives a detailed descripton of types of victims and petrpetrators, especially of the ones who are involved in aforementioned crimes.