To lower the formaldehyde emission of wood-based composite panels bonded with urea-formaldehyde (UF) resin adhesive, this study investigated the influence of acrylamide copolymerization of UF resin adhesives to their chemical structure and performance such as formaldehyde emission, adhesion strength, and mechanical properties of plywood. The acrylamide-copolymerized UF resin adhesives dramatically reduced the formaldehyde emission of plywood. The C-13-NMR spectra indicated that the acrylamide has been copolymerized by reacting with either methylene glycol remained or methylol group of UF resin, which subsequently contributed in lowering the formaldehyde emission. In addition, an optimum level for the acrylamide for the copolymerization of UF resin adhesives was determined as 1%, when the formaldehyde emission and adhesion strength of plywood were taken into consideration. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 3181-3186, 2010