The route of aerobic soil degradation of tebufenozide was investigated at 20 °C in four soils (sand, pH 5.52; loamy sand, pH 5.52; sandy loam, pH 6.4; loamy sand pH 6.0) using tebufenozide radiolabeled in the ethylbenzoyl ring. In all soils, mineralisation to CO2 was the major route of degradation (27.2 - 38.7 % at day 120). However, intermediate degradation products were determined with maximum concentrations between 8.0 and 20 %. RH-2651 was found to be the major metabolite (maximum values between 11 and 20 % AR after 29 or 64 days), but it degrades rapidly decreasing to approx. 30 % of its maximum level 30 days later. RH-2703 and RH-6595 were also identified as metabolites, but their levels were always below 10 %, and degradation of these metabolites was observed. The metabolite RH-6595 accounted for more than 5 % AR in two sequential measurements in two soils (max. 8.8 %). Metabolite RH-2703 concentrations were between 5 and 8 % only at one measurement. Two unknown polar metabolites were below 2 % (M1) and 9.1 % (M2), respectively. However, metabolite M2 accounted for more than 5 % of the amount of active substance added to the soil in at least two sequential measurements in one soil (5.3 and 9.1 % AR), according to the current assessment of the soil degradation studies. High levels of bound residues were formed and reached maxima of 37.1 - 42.8 % at day 120 (study end). Tebufenozide was relatively insensitive towards photodegradation. Small amounts (< 6 %) of RH-6595 and the B-ring aldehyde were formed over 30 days, and a first order DT50 of 98 days was calculated for tebufenozide.