Four Pseudomonas spp. were isolated from a soil consortium enriched from soil contaminated with 2,4,6-trinitrotoluene (TNT). All four species extensively transformed TNT The rate of transformation varied among species. In isolate 4, 100% of TNT (100ppm) was transformed in 4 days. The TNT transformation was achieved by the four isolates through a co-metabolic process with a succinate co-substrate. The four isolates produced NO2-from TNT The maximum NO2- production, observed for isolate 1, was equal to 30% of the NO2- available from the nitro groups of TNT For other isolates the NO2- production varied from 10 to 16%. The radiolabeling studies showed signs of ring cleavage. Isolate 3 used 13% of C-14-TNT to make cellular material, and isolate 4 converted 6% of C-14-TNT to biomass. The production of C-14-CO2 was observed for all four isolates, but the amount of C-14-CO2, produced was quite low: isolate 4 produced C-14-CO2,from approximately 1% of C-14-TNT The rate of degradation of TNT intermediates was very slow, reflecting possible difficulties in metabolizing the intermediates of TNT to CO2. The main intermediates were identified as 4-amino-2,6-dinitrotoluene. and 2-amino-4,6-dinitrotoluene.