Seven thermophilic species were isolated from various thermogenic habitats on modified Czapek's Dox agar medium with CMC replacing glucose. The isolated fungi were identified based on their morphological characters and sequence homology of their rRNA gene sequences. Congo red test was used to display their cellulolytic activity. The cellulolytic activity (FPase, CMCase and β-glucosidase) of five selected species were performed on solid state fermentation (SSF). Thermoascus aurantiacus MW559792 and Mycothermus thermophilus MZ723073 were selected for optimization experiment based on their maximum productivity of cellulases. Culture conditions were optimized under SSF experiment. Of the five lignocellulosic wastes used as carbon sources, rice straw was the most favorable for maximum production of FPase (1.78, 1.45 U/g), CMCase (6.18, 4.09 U/g) and β-glucosidase (31.93, 16.23 U/g) from T. aurantiacus and My. thermopilus respectively. The suitability of the lignocellulosic substrates was in the following order: rice straw> maize straw > wheat straw>corn cob> rice hulls. Peptone was the most suitable nitrogen source for maximum FPase (1.88, 1.46 U/g), CMCase (7.02, 4.89 U/g) and β-glucosidase (28.60, 19.91 U/g) activities by T. aurantiacus and My. thermophilus respectively. Nitrogen sources availability was in the following order: Peptone > Yeast Extract>(NH₄) ₂SO₄> Beef Extract> NH4NO3> NaNO3> KNO3. The maximum cellulolytic activities of T. aurantiacus and My. thermophilus were also achieved at pH 5, 50°C and 45°C and 4 to 6 days of incubation respectively. On that bases T. aurantiacus MW559792 and My. thermophilus MZ723073 were suggested to use industrially for bioconversion of lignocellulosic wastes at saccharification stage.