The antibacterial behavior of transition metals (Cu or Ag)-plated activated carbon fibers (ACFs) was investigated. The pore Structure of the ACFs before and after metal electroplating was studied by N-2/77 K isothermal adsorption. The antibacterial behavior against Staphylococcus aureus and Klebsiella pneumoniae was tested by a modified dilution method. As experimental results, the ACFs showed a decrease in specific surface area and micro- and total pore volume with increasing metal content. The antibacterial behavior of the ACFs was predominantly increased and showed over 99% against S. aureus as well as K. pneumoniae, attributed to the presence of metal nanoparticles in this system. (C) 2008 Elsevier Inc. All rights reserved.