ABSTRACT: Chlorinated ethenes are one of the most observed groups of ground water contaminants. Their occurrence in saturated and unsaturated zone is mainly affected by geological conditions, their physicochemical properties and ability to be biodegradated. Contamination of ground water by chlorinated ethenes was observed at 6 localities in the eastern part of the Czech Republic (dry cleaning facilities, storages and landfill). Marked zones of higher contaminants concentrations were found in the lower or upper parts of saturated zone (homogenous porous media), These zones reflect the source of contamination, where the presence of DNAPL is likely. The persistence of the zones with higher contaminants concentrations is time-limited and space-limited, often significantly depending on ground water regime changes. The biodegradation occurred at all localities, byproducts typical for the presence of anaerobic conditions were found. The complete description of biodegradation was limited due to lack of data on daughter products concentrations. The adequate quantity of primary substrate was found to be the main limiting factor in biodegradation processes.