||The main objective of this thesis is to provide the reader a basic knowledge about the issue of effective and nominal corporate tax rates. The theoretical part is concerned with the different approaches to the effective tax rates and with the corresponding methods of their calculation. The main contribution of the thesis presents the empirical part, which tries to assess the real corporate tax burden of Czech companies. The data required for the computation were collected according to PX stock-index and we applied the methods of backward- looking micro approach. The obtained results were subjected to a thorough analysis. In fact, the companies taking part in the research pay on average the income tax 17,07% in the period 2008-2012, which is significantly lower than the nominal tax rate 19%. Although the current academic literature reports about steadily declining effective tax rates, it does not correspond to our results. The reason for this might be caused by the nature of micro method used, that reflects the sensitivity of the economic cycle’s development. The observed period in the research coincides with the time of the world economic crisis, that may inflict an undesirable bias.