Quaternary ammonium salts immobilized onto poly(2-N,N-dimethylaminoethyl) methacrylate and a mixed network of poly(oxyethylene) and poly(4-vinylpyridine) were prepared. These salts were characterized by an elemental analysis, LR, H-1 and C-13 NMR spectroscnpy. The catalytic activity of the polymeric complexes was studied in the epoxidation of styrene as a model reaction. The system under study consisted of a water-immiscible solvent, aqueous hydrogen peroxide and Na2WO4/H3PO4. The catalytic activity of the polymeric ammonium salts depends on the kind of support employed, as well as on the length of hydrocarbon radicals and the nature of the anion. An increase in the selectivity of the reaction as compared to a system with non-immobilized salts is observed. (C) 2000 Elsevier Science B.V. All rights reserved.