In the process of making ethanol from lignocellulosics, enzyme production is still the most crucial and costly step. Trichoderma reesei Rut C-30 is the best known cellulase producer. This fungus is very good in endo- and exoglucanase production, however, the amount of β-glucosidase excreted is not sufficient for hydrolysis. In addition, T. reesei Rut C-30 is sensitive to inhibitors generated during steam-pretreatment of wood. In the present study, two good cellulase producers were selected from 16 fungal strains and investigated regarding filter paper activity (FPU) and β-glucosidase activity using inexpensive lignocellulosic carbon sources for cultivation. T. reesei Rut C-30 proved to be a good cellulase producer, resulting in a maximum FPU of 1.39 FPU ml &1 on washed, steam-pretreated willow, but the β-glucosidase activity was insufficient. High β-glucosidase activities were reached with T. viride OKI B1 on all substrates, with a maximum activity of 1.62 IU ml &1 on steam-pretreated spruce.