Silver nanoparticles were coated onto cotton fabrics with 3-mercaptopropyltrimethoxysilane (3-MPTMS). The coating process was accomplished by soaking the cotton fabrics into silver colloid/3-MPTMS solution at 43 degrees C for 90 min. The coated fabrics were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). SEM images showed a layer of silver nanoparticles and 3-MPTMS on cotton. The XPS data showed that distinguishable binding energy peaks of Ag 3d, Si 2p, Si 2s, S 2p were 368/374, 102, 153, and 162 eV, respectively, which confirms the existence of silver and 3-MPTMS on cotton fabrics. The treated cotton fabrics showed prominent antimicrobial effectiveness against Staphylococcus aureus (ATCC 6538) and Klebsiella pneumonia (ATCC 4352). Furthermore, the laundry test showed that 66% of silver nanoparticles were retained after five washing cycles. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119:2261-2267, 2011