ABSTRACT: This paper deals with cleaning of soils and groundwater contaminated with chlorinated hydrocarbons. EPS – ClU is a new aerobic remedial technology able to convert TCE and DCE to water, carbon dioxide and chlorides with the help of special aerophillic bacteria. This technology was used for the first time at Ceska zbrojovka, a.s. – Uhersky Brod. Old environmental contamination was related to saturated and nonsaturated zones. The highest contamination was found to be present at well Z-4. The sum of chlorinated hydrocarbons ΣCl-Eth < 1 500 ug.l-1 in groundwater was set as target limit. During cleaning process nutrients concentration, concentrations of PCE, TCE and DCE, number of microorganisms in the groundwater and groundwater parameters (pH, O2, Eh, Cl-) were monitored. The sum of chlorinated hydrocarbons ΣCl-Eth in groundwater was reduced from 22 899 ug.l-1 to 391 ug.l-1 by aerobic bioremediation from May till June 2007.