Crosslinked polystyrene ethylene glycol acrylate resin (CLPSER) was developed for the immobilization of the enzyme catalase by the introduction of a crosslinker, O,O'-bis(2-acrylamidopropyl) poly(ethylene glycol)(1900), to styrene. The crosslinker was prepared by the treatment of acryloyl chloride with O,O'-bis(2-aminopropyl) poly(ethylene glycol)(1990) in the presence of diisopropylethylamine. The resin was characterized with IR and C-13-NMR spectroscopy. The catalytic activity of the catalase-immobilized system of CLPSER was compared with divinylbenzene-crosslinked polystyrene, ethylene glycol dimethacrylate crosslinked polystyrene, and 1,4-butanediol dimethacrylate crosslinked polystyrene systems. Crosslink levels of 2, 8, and 20 mol % were evaluated. Among these crosslinked systems, the 2 mol % system was found to be most suitable to support catalytic activity. When a long flexible hydrophilic poly(ethylene glycol) crosslink, introduced between the polystyrene (PS) backbone and functional groups was used for immobilization, the extent of coupling and enzyme activity increased. Depending on the nature of the support, the catalytic activity of the system varied. The hydrophilic CLPSER support was most efficient for immobilization compared to the other PS-based supports. © 2005 Wiley Periodicals, Inc.