An aerobic bacterial consortium was shown to degrade 2,4,6-trinitrotoluene (TNT). At an initial concentration of 100 ppm, 100% of the TNT was transformed to intermediates in 108 h. Radiolabeling studies indicated that 8% of [C-14]TNT was used as biomass and 3.1% of [C-14]TNT was mineralized. The first intermediates observed were 4-amino-2,6-dinitrotoluene and its isomer 2-amino-4,6-dinitrotoluene. Prolonged incubation revealed signs of ring cleavage. Succinate or another substrate-e.g., malic acid, acetate, citrate, molasses, sucrose, or glucose-must be added to the culture medium for the degradation of TNT. The bacterial consortium was composed of various Pseudomonas spp. The results suggest that the degradation of TNT is accomplished by co-metabolism and that succinate Serves as the carbon and energy source for the growth of the consortium. The results also suggest that this soil bacterial consortium may be useful for the decontamination of environmental sites contaminated with TNT.