Cellulase is a synergistic enzyme that is used to break up cellulose into glucose or other oligosaccharide compounds. The study focuses on the production of cellulase from A. niger. The physico-chemical conditions such as pH, temperature, inoculum size, fermentation period, static and agitation conditions, effect of different carbon and nitrogen sources were studied and optimized for cellulase production by A. niger. Banana pseudostem waste proved to be the best carbon source for cellulase production and peptone proved the best nitrogen source for cellulase production. Maximum cellulase production obtained at broad pH and temperature ranges. Inoculum size 10 discs of 8 mm size, incubation of 72 h and at 35⁰C fermentation temperature obtained maximum cellulase activity. Cellulase production by A. niger at 120 rpm found best. All these results proved applicability of cellulase enzyme produced by A. niger in various industrial and biotechnological applications.