The efficiency of adding chlorophenol-degrading microorganisms to contaminated soil was studied with focus on soil parameters (pH, organic carbon etc.) influencing the degradation. The degradation of 2,4,6-trichlorophenol by Azotobacter strain GP1 in a non-sterile loamy sand was accompanied by a stoichiometric release of chloride (3 mol of chloride per mol 2,4,6-trichlorophenol) after an incubation of 2 days suggesting a complete degradation of 2,4,6-trichlorophenol without accumulation of any metabolites. In soils without Azotobacter sp. strain GP1 after 24 hours no decrease of 2,4,6-trichlorophenol was observed, however after two weeks of incubation only 60 percent of the 2,4,6-trichlorophenol was detected. This decrease of 2,4,6-trichlorophenol was not accompanied by a release of chloride.