A chloroaniline-degrading bacterial strain isolated from polluted sediment in the Mekong River was identified as Geobacter sp. KT5. The obtained isolate was found to utilize a wide range of trichloroanilines (TCAs), dichloroanilines (DCAs), monochloroanilines (MACs), and aniline as sources of carbon and energy. It also used Fe(III) as a terminal electron acceptor under anaerobic conditions. Among the chlorinated anilines, KT5 utilized 2,3,4-trichloroaniline (234TCA) with the highest rate (2.48 +/- 0.32 mu M day(-1)). On determining the degradation pathway for chloroanilines (CAs) in Geobacter sp. KT5, it showed that the removal of ortho and para halogen was dominant. Firstly, KT5 ortho-dechlorinated some TCAs to DCAs, and then reductively transformed them into MACs and aniline prior to complete degradation with the iron reduction stoichiometry and release of nitrogen and chlorine. The KT5 augmentation in sediment slurry enhanced the degradation of CAs and aniline; however, the anaerobic degradation rates in slurry were significantly lower compared to those in liquid media.