A preparative scale biomedical sample purification system that combines the high resolution power of flow Field-Flow Fractionation (flow FFF) with rapid membrane filtration methodology is proposed. This proposed two dimensional system is fundamentally simple and is applicable to many biomedical samples such as proteins, anti-bodies, polypeptides, cell and subcellular particles, and immobilized drug delivery systems. The proposed flow FFF/filtration system utilizes the separation power of flow FFF in the first dimension and th rapid filtration and concentration power of membrane technology in the second dimension. Our initial evaluation on several commercially available membranes indicate a satisfactory match of the desired basic membrane properties with the measured molecular weight cut-off and sample recovery. The expected outcome to this development is a preparative scale rapid biomedical purification system which should certainly benefit many biomedical research and applications in bio- engineering and pharmaceutical industries.