The present diploma thesis is focused on the definition of differences resulting from the comparison of two chosen forms of doing business of a foreign person in the Czech Republic. It specifies differences from the viewpoint of the commercial law and the obligations as an accounting unit. Foremost, the thesis includes a detailed analysis from a tax point of view. The thesis involves a model example to define the precise amount of tax obligation incumbent on the both forms of business of a foreign person in the Czech Republic. This model example constitutes a basis for the final evaluation and to draw relevant conclusions. Suggestions and recommendations mentioned in this work can serve as an overview of the approach to the taxation of cross-border income and at the same time as a tool for the elimination of errors and discrepancies in connection with the chosen form of business of a foreign person in the Czech Republic.