In the industrial polyolefin production processes, quality improvement has been attracting considerable attention. In most polymer production precesses, blenders are installed downstream of the production line for damping out quality variation. It is an admission of the fact that the conventional way of reducing quality variation is unable to provide acceptable solution of satisfying the increasing demand from customers for the highest possible quality. Therefore, the cooperative blending operation is pursued optimally at the blender units. In this paper, an optimal blending operation is discussed. The optimal blending scheme is derived by solving a mixed integer linear programming problem (MILP). The scheme is tested on an industrial blender process of the polyethylene production plant. As a result, the optimal blending operation reduces the variances of the final product quality dramatically.