The degradation of benzene in pasteurized spent mushroom substrate (SMS) was assessed. Following a 3 month enrichment in the presence of a variety of BTEX compounds, the extent of [U‐14C]benzene mineralization in the pasteurized SMS increased with increasing incubation temperature (18°C<37°C<50°C). The concentration as well as the chemical composition used to enrich the compost's degradative activity was also shown to be involved in determining the extent of benzene mineralization. SMS induced on a 12.5 mM BTEX mixture mineralized more benzene than composts induced using 500 μM benzene, 500 μM o‐xylene, or 2.5 mM BTEX mixture. In the absence of a pre‐enrichment period, benzene mineralization was minimal.