Aspergillus japonicus produces carboxymethyl cellulase (CMCase), filter paperase and β-glucosidase in various cellulosic media. Cotton activity could not be detected in the media. The growth and production of cellulolytic enzyme of this fungus are highly favored on carboxy methyl cellulose (CMC), jute powder, wheat bran and barley husk in comparison with microcrystalline cellulose (MCC) and absorbent cotton. CMCase and β-glucosidase are simultaneously induced by inducers such as CMC. Cessation of induction is noticed with inhibitors like cycloheximide and ethidium bromide. When glucose was added in the growth medium, further utilization of CMC was prevented and CMCellulase synthesis was inhibited, suggesting catabolite repression. © 1988.