Due to their high metabolic diversity and high adaptability, microorganisms are able to live in the most varied of "natural" and "artificial" habitats created by environmen- tal contamination. Different microbes can use a great variety of refractory pollutants, thus permitting their use in ex and in situ bioremediation. The implementation of biotreatment processes requires the use of evaluation methods of pollution and the success of bioreme- diation. The microorganisms can also be used as biosensors. Laboratory microcosm exper- iments would allow isolation of new microorganisms, assessment of the methods for eval- uating pollution and the risk of implementation of non- and recombinant microorganisms. Bioremediation technologies have an open future linked to multidisciplinary scientific work.