The presence of chemical warfare agents in the environment may cause significant damage to human, animal and plant health. Chemical agents present an equal threat to the military and the civilian population, primarily because of its potential use in terrorist attacks. The effects of chemical attacks may be avoided by timely application of decontamination methods – mechanical, chemical, physical or combined. The main goal of this thesis is to describe different decontamination methods, especially the chemical decontamination, and to provide insight into the development of new methods. Chemical decontamination encompasses chemical agents decomposition mechanisms, which break them down into non-toxic products through hydrolysis, oxidation and elimination. The chemical reactions and decontamination substances are thoroughly analyzed, and the potential biological activity of the decomposition products are examined.