The route and rate of degradation of metobromuron under aerobic conditions was investigated in two acceptable laboratory studies using [phenyl-U-14C]-metobromuron. Results are available for five soils at 20 or 25°C. Only minor degradation products were formed in aerobic conditions. They all remained below 5% AR at all sampling times. Four of the degradation products were identified as desmethoxy-metobromuron (=R2, max. 3.0% AR), desmethyl-metobromuron (=R1, max. 1.2% AR), 4-bromophenylurea (=R3; max. 1.8 % AR) and 4-bromoaniline (=R4, max. 1.7% AR). Mineralisation to CO2 occurred up to 27.3 % AR (day 168, study end). High amounts of non-extracted residues were formed in all five soils. These accounted up to 74.1% AR (day 118, study end) and were mostly associated with humins and humic acids. Because the extraction method was adequate, these non-extracted residues are not considered to be bioavailable. Therefore they are not taken into account for soil risk assessment. The degradation of metobromuron under laboratory aerobic conditions followed single first-order kinetics with DT50 values ranging from 24.6 to 49.7 days. The corresponding DT90 values ranged from 81.3 to 165.1 days. The normalised (20°C, pF2) geometric mean DT50 value is 34.3 days.