A novel adsorbent, a crosslinked starch microsphere (CSM), was prepared from soluble starch and N,N'-methylenebisacrylamide. The microporous structure of the CSM was determined with scanning electron microscopy. The diameter distribution of the CSMs was quite uniform, and the average diameter of the microparticles was estimated to be 50 mu m. Cu2+ was introduced into the CSM. The successful adsorption of Cu2+ in the CSM was confirmed with Fourier transform infrared spectroscopy. The crystal structure of the CSM was destroyed after the incorporation of Cu2+. This was proven with X-ray diffraction. The thermal stability of the CSM was weakened with the introduction of Cu2+ during simultaneous thermal analysis. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 487-490, 2010