The aim of the thesis is to analyze the applied environmental taxes in the Slovak Republic compared to Denmark. Assessing their effectiveness and enhancing the greening of the tax system in the form of introducing new taxes with environmental aspects, or proposals for raising tax rates for environmental protection. The theoretical part deals with the characteristics of environmental policy and its economic instruments in the form of taxes, with a description of their functions. For the realization of the application part, it was necessary to monitor the statistical data of selected countries and to study in detail the objectives of the environmental fiscal reform. The final part of the thesis is focused on the mutual comparison of the selected countries. The comparison made it possible to understand the functioning of environmental taxes in Denmark and helped to process new proposals for the SR.