Xylanase enzymes are group of enzymes that can degrade Xylan present in plants. Xylan lignin and cellulose formed a complex matrix in plants. Lignin imparts colour to cellulose and thus eventually imparts colour to paper and pulp. Xylanase facilitates the removal of lignin from the paper pulp thus improves the brightness of paper. Xylanase was produced by Aspergillus niger using different carbon sources. UV irradiation of Aspergillus niger slightly improves the Xylanase activity than native Aspergillus niger. Twenty minutes exposure of Aspergillus niger to UV irradiation was considered suitable for the production of Xylanase. Wheat bran with 3.5% concentration was considered best substrate for Xylanase production than corn cobs and sugarcane baggasse. Maximum Xylanase production was observed at 30oC and pH 5.6.