A novel vinyl-hydantoin monomer, 3-(4 ' -vinylbenzyl)-5,5-dimethylhydantoin, was synthesized in a good yield and was fully characterized with Fourier transform infrared (FTIR) and H-1 NMR spectra. Its homopolymer and copolymers with several common acrylic and vinyl monomers, such as vinyl acetate, acrylonitrile, and methyl methacrylate, were readily prepared under mild conditions. The polymers were characterized with FTIR and H-1 NMR, and their thermal properties were analyzed with differential scanning calorimetry studies. The halogenated products of the corresponding copolymers exhibited potent antibacterial properties against Escherichia coli, and the antibacterial properties were durable and regenerable. The structure-property relationships of the polymers were further discussed.