The environmental fate of tralkoxydim was investigated in a number of laboratory studies using either CH-14C or PH-14C ring labelled material. Results of the laboratory aerobic route and rate of degradation studies carried out at 5, 10 or 20°C and 40% of the Moisture Holding Capacity were available for 6 different soils. Two major metabolites (>10% AR) were identified as R173642 (3-(2,4,6- trimethylphenyl) pentanedioic acid) which peaked at 17.2% AR after 15 d and R223068 (4-[2-(1-{ethoxyimino}propyl)-3-hydroxy-2-cyclohexene-1-one-5-yl]-3,5- dimethyl benzoic acid) which also peaked after 15 d at 12.5% AR. Additionally metabolite R163434 (3-ethyl-4,5,6,7-tetrahydro-4-oxo-6-(2,4,6-trimethylphenyl)-1,3- benzoxazole) was observed at >5% AR in at least 2 consecutive sampling points in one soil (peak formation of 7.5% AR) and therefore requires further consideration according to the guidance document on the assessment of the relevance of metabolites in groundwater (Sanco/221/2000-rev.10, 25 February, 2003). Mineralisation was a significant route of dissipation, with up to 55.1% AR evolved as 14CO2 after 94 d. Unextracted residues peaked at 47.6% after 14d before declining towards the end of the incubation period in most soils.