The subject of this diploma thesis is the tax optimisation of a selected business entity. The thesis aims at finding the most optimum tax solution possible, especially of corporation income tax in order that the selected entity has as low tax liability as possible. The diploma thesis is divided into a theoretical and practical part, each of which is divided into individual chapters and subchapters, dealing with specific problems. The introduction of the theoretical part includes basic terms relating to tax issues, general data on the taxation system of the Czech Republic. The following and, simultaneously, most comprehensive chapter is devoted to corporation income tax, namely for the reason that the practical part deals with alternatives o...