||The aim of this thesis is to provide a description of the phenomenon of tax havens in relation to the Czech Republic. The thesis begins with description of theoretical background of the problem. It provides definition, characteristics, and an overview of main uses of tax havens by Czech firms. This part is followed by analysis of Czech firms controlled from tax havens in order to determine what type of firms is most often leaving the Czech Republic. The analysis showed the largest interest from limited liability companies and companies operating in real estate. The next part of the thesis presents an estimate of tax loss arising from tax haven activities of Czech subjects. It is the first estimate of this kind for the Czech Republic. The resulting tax loss is estimated to be 21 billion CZK per year, which equals to approximately 10% of annual tax revenue from corporate and personal income tax. The thesis is concluded with an overview of counter-measures that are taken worldwide and in the Czech Republic as means of combating the rising phenomenon of tax havens.