Taxes are the most important source of the public revenues and in the most of the modern countries public revenues structure prevails as the largest item. Throughout the history taxes receives its importance which ultimately resulted in great number of tax forms. Both legal entities and natural persons are the subjects of taxation. From the viewpoint of legal entities (businesses subjects), subjects of taxation are their inputs, outputs, and positive financial result (profit). The subject of this thesis is the taxation of business subjects. During its business activities, companies are obliged to pay the certain taxes. Therefore, there are different sorts of taxes that the company pays: input and output taxes, taxes levied on gross salary of the employees, then the taxes paid on the profit. Each of these mentioned has its own characteristics and tax rates that will be considered in the work. The purpose of this thesis is to present all the taxes that one business entity must pay in its business activities. Taxation of sole proprietorship is also considered. Thesis consists of two parts; in the first part attention is paid to the conceptual definition of tax and the tax system, while the second part deals with the taxation of business entities.