Color is major problem in waste water from OCC based mills. Presence of color in waste water from OCC based recycled paper mill owes to the way that cardboard container is made. Corrugated cardboards are made up of kraft papers, a kind of paper which resists tearing, splitting, and bursting. These kraft papers are either made of virgin wood or non-wood fibers or recycled paper fibers. For making top quality boxes, generally virgin Kraft is used for making cardboard boxes. It doesn’t really matter whether the paper is recycled or not, ultimately it always starts as virgin kraft paper. Generally, color of kraft paper is brown but it also depends upon the type of tree or wood fibers it has come from. Lignin is the main compounds responsible for the color of wood and in turn gives the same color to the kraft paper made from that wood. Sometimes, color of kraft paper is altered by adding dyes during process for producing colored kraft paper. Hence, the color of waste water generated from OCC based recycled paper mill depends upon the types of kraft paper produced, color of kraft paper used for making OCCs and color of dyes used for producing colored kraft paper. Lignin and dye are very complex organic compounds which show high stability to degradation during secondary biological treatment (Cecen et al., 1992; Allen and Koumanova, 2005). For removing lignin and dye from OCC based paper mill waste water, electrochemical oxidation technique can be very effective. In recent years, there has been increasing interest in the use of electrochemical techniques [7,8,9,10] for the treatment of industrial waste water but no work has been reported for treating OCC based recycled paper mill effluent using this technique. During the electrochemical oxidation process, the color causing compounds in paper mill effluent water such as lignin and dyes can be destroyed.