Background: In the present study, optimized cultural conditions for enhanced production of xylanase from local soil isolate of Trichoderma species, using water hyacinth as a substrate in submerged culture fermentation is presented. Method: The Megazyme assay method was used for endo 1, 4-?-xylanase using Azo-xylan (Birchwood). Results: A continuous increase in xylanase production was observed with increasing level of substrate concentration in the medium and highest production was obtained with water hyacinth at 6% w/v level. Maximum xylanase production was achieved with a pH 5.0, incubation temperature of 30ÂºC and agitation rate of 150 rpm. The highest production was achieved on day five of fermentation at optimum parameters under study. Result: The study showed that production of xylanase can be cost effective using water hyacinth and can be implored on large scale for industrial applications.