Abstract The white‐rot fungus Nematoloma frowardii was examined for the ability to degrade [ring U‐14C]‐phenanthrene and [4,5,9,10‐14C]pyrene in liquid and solid (straw) cultures in a period of 63 days. 3.2% phenanthrene and 8.6% pyrene were mineralized to 14CO2 in liquid cultures, respectively. A considerable higher mineralization of 11.2% (phenanthrene) and 46.5% (pyrene) was detected in straw cultures. Metabolites were identified by their UV absorption spectra. N. frowardii transformed phenanthrene to phenanthrene 9,10‐dihydrodiol. Pyrene 4,5‐dihydrodiol was identified as major metabolite in pyrene degradation.