Microcapsules with epoxy curing agent were successfully prepared by an in-situ polymerization route with epoxy resin and poly-(urea-formaldehyde) as core and shell materials, respectively. The synthetic conditions were optimized by a comprehensive investigation on raw materials consumption, size distribution, and surface morphology. Preparation of microcapsules with high wrap ratio was also demonstrated. The as-synthesized microcapsules were studied using various characterizations techniques, including optical microscope, fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and contact angle meter. Spherical microcapsules (size: similar to 60 mu m) with smooth surface were obtained when the stirring rate was 400 rpm and the amount of core materials is 76 wt %. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 2162-2169, 2010