Xylanase is a naturally occurring enzyme found in microbes and fungi. Xylanase belonging to pentosanases, a class of enzyme which breaks down cell wall matrix of plants breaks down xylan into xylose. Thus this property of xylanase makes it important at commercial level. Recently, xylanases are being produced by the help of genetically modified organisms (bacteria and fungus). Xylanases also find its application in various industries. These include textile and paper industry, beverage industry, bakery industry, pharmaceuticals industry, biofuel production. In this review we are tried to highlight the importance of xylanase at commercial level.