In aerobic conditions, the degradation of bifenthrin proceeds via hydrolysis and/or oxidation, resulting in the formation of a variety of minor metabolites, non-extractable residues (max. 23.9 %, 180 d, acid label and 24.9 %, 120 d, alcohol label) and ultimately carbon dioxide (max 49.7 %, 46 d, acid label and 36.2 %, 126 d, alcohol label). Soil residue studies showed that levels of organosoluble radioactive residues decreased with time as levels of postextraction solids (PES) increased. The data indicated that parent compound is the only relevant residue for quantification in soil. The main metabolite, 4’-OH bifenthrin, is always found in amounts less than 8.2 % (120 d, alcohol label) except in one soil where 14.1 % (acid label) were found after planting lettuce 60 d after treatment. Generally, other metabolites such as TFP acid, BP alcohol or BP acid mostly occurred in traces only. Yet, in one field study, TFP acid has been found as a major metabolite (max 11.6 % AR, 120 d). The ecological relevance of this metabolite for terrestrial organisms should be documented. If necessary, DissTx will be estimated for PECs / PECgw / (PECsw with runoff and drainage) calculations. Soil bound residues are almost equally distributed among the various soil organic matter components humic acid (5.2 – 7.3 %), fulvic acid (3.0 – 4.8 %) and humin (4.0 – 7.2 %). One year after application, these metabolites were merely noted in trace amounts, and there was no tendency for accumulation in soil as indicated by the results of soil residue studies including rotational crops planting.