Contaminated soils pose a threat to the environment in many parts of the world. Pollutants incineration with soil and in situ, on situ or ex situ thermal desorption are applied to interrupt the transfer of pollutants to the environment and to decontaminate the soils. Nevertheless, in both methods, it is necessary to consider their paradox property – they might generate products, which are even more toxic than the primary pollutant. Thermal desorption is a thermally induced physical separation two-stage proces. The first stage is the evaporation of water and pollutants, the second stage is the capture and destruction of pollutants. It is arranged either as a combustion plant (e.g., the destruction of evaporated hydrocarbons by flame), or the pollutants are oxidized using a heterogeneous catalyst. It is also possible to condense the outgoing vapours and then either to transport the condensate with the pollutants into a suitable incinerator, or to chemically neutralize and/or decompose organic substances or mineralization products present in the condensate. The thermal treatment is often the most suitable method of cleaning contaminated soils to reach prescribed limits, especially, if the cleaning process should be fast and it is not necessary to transport the contaminated soil to long distances. Thermal desorption units are commercially available in many variations and easily transportable.\n