The study was conducted for the production of cellulase enzyme through liquid state bioconversion of palm oil mill effluent (POME) by filamentous fungi and characterization of the produced enzyme. Several experiments such as selection of filamentous fungi, optimization of media and process parameters, development of the separation/purification conditions for ultra-filtration, characterization and evaluation of purified cellulase enzyme through hydrolysis of oil palm empty fruit bunches (EFB) were carried out to achieve the entire objectives of the study. The results on isolation indicated that among the strains isolated, the strains IBPC108R, IBEC302B and IBEC305B gave the highest FPAse activity (0.3 U/ml) after 2 days of fermentation and IBEC302B showed the highest CMCase activity (0.42 U/ml) after 3 days of fermentation. Among the laboratory stocks, Aspergillus IBO-102MNB, gave the highest FPAse activity (0.28 U/ml) and Aspergillus IBO-103MNB gave the highest CMCase activity (0.62 U/ml) after 2 days of fermentation. Among the strains tested, the Trichoderma reesei RUT C-30, a commercial