The metabolic pathway of Pyrimethanil under aerobic and anaerobic conditions was identical in all soils tested. Metabolism starts with the biotic cleavage of the unsubstituted phenyl ring to 2-Amino-4,6-dimethylpyrimidine as the predominant metabolite. No intermediates were detectable and relative high 14CO2 evolution was shown from this label position. Only minor side reactions to two nitro-substituted derivatives and minute amount of one N- oxide could be observed. N-hydroxylation of the amine as another minor side reaction leads to 2-Hydroxy-4,6-dimethylpyrimidine. It is suggested that the majority of the aminopyrimidine directly forms irreversible bonds with the soil organic matter (non extractable residues). Finally, as part of the metabolic turnover of the organic soil material, the bound residues are completely mineralised to CO2. Some of the aminopyrimidine must be mineralised also directly because the CO2 evolution from this part of the molecule was also high.