A consortium of anaerobic microorganisms was grown on acetate, ethanol, glucose or methanol and dechlorinated 50 umol 2,4,6-trichlorophenol, through 2, 4-dichlorophenol, to 4-chlorophenol. The highest rate of dechlorination of 2,4, 6-trichlorophenol was observed when ethanol was used as a growth substrate.