We investigated the metabolism of 3‐nitrofluoranthene by filamentous fungus, Cunning‐hamella elegans ATCC 36112. Cunninghamella elegans metabolized about 72% of the 3‐nitro[3,4‐14C]fluoranthene added during 144 h of incubation to 2 major metabolites. These metabolites were separated by reversed‐phase high‐performance liquid chromatography and identified as 3‐nitrofluoranthene‐8‐sulfate and 3‐nitrofluoranthene‐9‐sulfate by ‘H nuclear magnetic resonance, UV‐visible, and mass spectral techniques. These results, in conjunction with previous studies on the fungal metabolism of fluoranthene, indicate that the nitro substituent at the C‐3 position of fluoranthene sterically hinders epoxidation and shifts metabolism to the C‐8 and C‐9 positions. Since the phenolic microsomal metabolites of 3‐nitrofluoranthene are mutagenic, the formation of sulfate conjugates of 8‐ and 9‐hydroxy‐3‐nitrofluoranthene by C. elegans suggests that the fungal metabolic pathways may be beneficial for detoxification of this ubiquitous pollutant.