A polymer membrane imprinted with quercetin has been synthesized in the presence of nickel(II) acetate as a metal ion mediator. A mixture of methacrylic acid (MAA), ethylene glycol dimethacrylate (EGDMA), tetrahydrofuran (THF) - methanol (3:1 v/v) as a solvent and Darocur (R) 1173 (2-hydroxy-2-methyl-1-phenyl-propan-1-one) as a photoinitiator was polymerized on a track-etched membrane (pores 0.4 mu m) used as a support. The polymer formed regular layers on both sides of the membrane and filled the pores. The highest initial flux of the template of 1.8 . 10(-7) mol . cm(-2) . h(-1) was observed for its diffusion from THF/acetate buffer (20:80, v/v) into THF. Membranes polymerized with nickel(II) were both more permeable and more selective. The maximum selectivity factors, calculated by using percent permeation, were 4.5 (quercetin/rutin) and 4.9 (quercetin/naringenin).