A microbial consortium that efficiently degrades 2,4,6-TCP (2,4,6-trichlorophenol), as the sole source of carbon and energy under aerobic conditions was selected from municipal activated sludge. Six bacterial strains, designated S-1, S-2, S-3, S-4, S-5 and S-6, were isolated from the selected consortium and five were identified as Sphingomonas paucimobilis (S-2, S-3), Burkholderia cepacia (S-4), Chryseomonas luteola (S-5) and Vibrio metschnikovii (S-6). After prolonged cultivation followed by successive transfers. the consortium's degradation ability was improved and reached a specific degradation rate of 34 mg 2,4,6-TCP g(-1) dry weight h(-1) (about 51 mg 2,4,6-TCP g-1 cell protein h-1). The soluble chemical oxygen demand, chloride and oxygen uptake balance data clearly indicate the complete dechlorination and mineralization of 2,4,6-TCP. The consortium's activity was not inhibited by 2,4,6-TCP concentrations less than or equal to400 mg l(-1). The highest specific growth rate (mu(max) of 0.01 h(-1)) was achieved at 2,4,6-TCP concentration less than or equal to200 mg l(-1), and the inhibition constant (K-i) was 610 mg l(-1) according to the Haldane inhibition kinetic model. An inoculum size up to 120 mg l(-1) cell dry weight is desirable in order to avoid a lag phase and to allow faster degradation of 2,4,6-TCP.