Microbial cellulose membranes have attracted a great deal of attention as novel wound-dressing materials, especially for the healing of skin burns and chronic wounds, because of their high water holding capacity and biocompatibility. However, the high humidity around the wound sometimes allows the growth of bacteria, as well as the regeneration of the tissue. In this study, silver nanoparticles were incorporated into the cellulose membranes via a chemical reduction method using a silver salt, silver nitrate (AgNO(3)) and a reducing agent, sodium borohydride (NaBH(4)). The silver nanoparticles were evenly adsorbed on the overall surface of the cellulose nanofibrils without any local aggregation and had a spherical shape with uniform size (8+/-2 nm) which allowed them to show antimicrobial properties. The interaction between the oxygen in cellulose and silver nanoparticles resulted in the stable adsorption of the silver nanoparticles on cellulose nanofibrils. The cellulose membrane with silver nanoparticles exhibited an antimicrobial activity of more than 99.99% against Escherichia coli and Staphylococcus aureus, so that it could be used as an antimicrobial wound-dressing material for chronic wounds and burns.