An indigenous bacterial strain MAM -24 was isolated from petroleum polluted soil by selective enrichment with 1,2,4-trichlorobenzene (1,2,4 -TCB) as the sole source of carbon and energy. During growth on 1,2,4 -TCB, growth by measuring O.D., protein measurement and bacterial count were determined. A stoichiometric amount of chloride ions is released. The degradation percentage of 1,2,4 -TCB was quantified by high performance liquid chromatography (HPLC). Bacillus mucilaginosus MAM-24 which have been identified by 16 S rRNA in a previous study was the best 1,2,4 -TCB degrader. It could degrade 99.3%, 98.0%, 98.6%, 99.3% and 14.4% of 5, 10, 15, 25, 50 µM 1,2,4 -TCB respectively. Degradation products of 1,2,4 -TCB was identified by gas chromatography mass spectrometry (GC -MS) analysis which revealed that isolate MAM -24 dechlorinated 1,2,4 -TCB as a first step. The corner stone of the intermediates was acetophenone.