Graft polymerization initiated by diperiodatocuprate(III) complex (Cu(III)) initiator was found to be an effective and convenient method for graft polymerization of vinyl monomers onto macroporous polyacrylamide gels, the so-called cryogels (pAAm-cryogels). The effect of time, temperature, monomer and initiator concentration during the graft polymerization in aqueous and aqueous-organic media was studied. The graft polymerization of water-soluble monomers as [2-(methacryloyloxy)ethyl]-tri-methylammonium chloride, 2-hydroxyethyl methaerylate, N-isopropylacrylamide, and N,N-dimethylacrylamide proceeds with higher grafting yield in aqueous medium, as compared with that in aqueous-organic media. Graft polymerization in aqueous-organic media such as water-DMSO solutions allows grafting of water-insoluble monomers such as glycidyl methacrylate and N-tert-butylacrylamide with high grafting degrees of 100 and 410%, respectively. It was found that the deposition of initiator on the pore surface of cryogels promoted graft polymerization by facilitating the formation of the redox couple Cu(III)-acrylamide group. (c) 2006 Wiley Periodicals, Inc.