[en] Three fungal species: Alternaria brassicola, helminthosporium sp. and verticillium agaricinum were incubated with radiolabelled methomyl (S¹4^C-methyl-N-[(methylcarbamoyl)oxy] thioacetimidate ). After filtration, the amounts of radioactivity in tissues and filtrates were analyzed for metabolic products. Of the applied radioactivity, the 3 fungal species were capable of degrading 38.9%, 35.3% and 29.3% into hydrolytic metabolites, respectively. Thin layer chromatographic analysis of hydrolytic fractions showed that two metabolic products ( unknowns 1 and 11 ) having R_f values of 0.30 and 0.47 could be detected in addition to a polar compound which contained the major radioactivity. The chloroform fraction contained mainly the parent material.2 tab