Under dark aerobic conditions, degradation of iprodione proceeds primarily via opening of the hydantoin ring to form the major metabolite carboxylic acid RP 35606 (max. 25.5% AR after 7 days). This compound can re-cyclize to the rearrangement metabolite RP 30228 (max. 29.5% AR after 30 days) or form the carbamoyl urea RP 36221 (max. 12.7% AR after 100 days). Iprodione was moderately fast degraded in soil under aerobic conditions, with an aerobic half-life between 6 and 90 days. Subsequent degradation leads to RP 32596 (max. 12.6% AR after 120 days) which is ultimately mineralized to CO2 or incorporated into bound residues. A minor degradation pathway for iprodione includes the formation of RP 25040 (max. 7.8% after 30 days) which is also be subject of further degradation. Non-extractable residues reach a maximum of 40.4-67.9% AR after 120 days. Characterisation of the non-extractable radioactive residues revealed that the major portion of radioactivity was tightly bound to the soil matrix or part of the humid acid fraction. Mineralization is low (0.6-1.9% AR after 120 days). There was some evidence that degradation of iprodione is pH dependant. The limit of pH 5.9 is considered as suitable by RMS.