To obtain fundamental information for the preparation of chromatographic type cellseparators, adhesion of canine peripheral lymphocytes and polymorphonuclear leukocytes (PMNs) onto synthetic polymer surfaces was examined with the use of newly developed "column method." Cells were found to hardly adhere on a nonionic hydrogel, PHEMA, which is supposed to have low interfacial free energy. One of the most cell-attractive surfaces among the samples examined was the surface coated with poly(p-diethylaminoethylstyrene) (P(p-EAS)). This polymer surface attracts significantly both PMNs and lymphocytes. To clarify the effect of charge on cell adhesion, the interaction of cells and a series of newly synthesized polyion complexes (PICs), ionic hydrogels, was also examined. Adhesion behaviors of lymphocytes and PMNs toward PIC surfaces were rather different from each other, and a possibility of separating PMNs and lymphocytes by PIC column was suggested. When the polymer surfaces were coated with canine serum prior to the cell-adhesion assay, they became nonadhesive to lymphocytes. However, only on PHEMA surface, the adhesion was enhanced by serum-precoating, probably because the interaction of adsorbed serum y-globulin and Fc receptor bearing lymphocytes.