Studies on cellulase production by Trichoderma reesei QM 9414 Mutant (T. reesei M) and Phanerochaete chrysosporium in flask Culture indicated suitability of water hyacinth (WH) as a Substitute for conventional wheat bran (WB) medium by Solid-State Fermentation (SSF). Maximum cellulase production was obtained with T. reesei M oil WH Substrate with Toyoma Ogowa (TO) medium at liquid /solid ratio of 2.5, and incubation period of 10 clays. However, T. reesei M failed to produce beta-glucosidase on WH medium. Further experiments on cellulase and xylanase production Were performed in Solid State Cabinet Fermenter (SSCF) to resemble conditions in tray fermenter, As compared to the flask Culture, cellulase production by T. reesei M was more in SSCF, and supplementation of TO medium with whey (40%) and peptone (0.15%) further enhanced production of both cellulase complex and xylanase by 2-3 fold. When Aspergillus niger was used in combination with T. reesei M, production of both cellulase and xylanase was enhanced considerably. The synergistic effect may be attributed to the beta-glucosidase production by A. niger which Could eliminate the inhibitory effect of cellobiose.