A new iodine-containing methacrylate monomer, 3,4,5-triiodobenzoyloxyethyl methacrylate (TIBEM), was synthesized by coupling 2-hydroxyethyl methacrylate (HEMA) with 3,4,5-triiodobenzoic acid. The monomer was characterized by H-1 nuclear magnetic resonance, infrared (IR), and ultraviolet spectra. Homopolymerization and copolymerization of the monomer with methyl methacrylate (MMA) were carried out using 2,2'-azobis isobutyronitrile as the initiator. A terpolymer of TIBEM, MMA, and HEMA was also synthesized. The copolymers were characterized by IR, gel permeation chromatography, differential thermal analysis, and thermogravimetric analysis (TGA). High molecular weight polymers were produced with MMA at different feed compositions of TIBEM. The polymers were found to be freely soluble in common solvents for acrylic polymers. TGA showed little decomposition of the copolymer below 280degreesC. Copolymers showed good radiopacity at 25 wt % of TIBEM in the feed. These copolymers could find applications in medical and dental areas where radiopacity is a desirable feature of the implants. (C) 2003 Wiley Periodicals, Inc.