Geothermal energy is an environmentally friendly source of energy that contributes and also will contribute increasingly to stabilizing energy supply in the future. In the world, geothermal energy ranks to the first group among the renewable energy sources with 52 % ratio on electricity generation and 79.6 % on direct use. Geothermal energy is utilized in 58 countries of the world. In Slovakia, only 3 % of the total consumption of primary energy sources is covered by renewable energy sources. Really utilizable potential of renewable and secondary energy sources (including geothermal energy) should reach 6.5 % of the total consumption in Slovakia in 2010 (according to Energetic Conception of the Slovak Republic, approved by the Slovak Government Resolution No. 562/1993). The number represents utilizable potential of 39 548 TJ (subtracting hydropower plants) and geothermal energy would occupy the second place with 18.1 % of the total utilizable potential.