This paper deals with the antibacterial efficacy of nanosized silver colloidal solution on the cellulosic and synthetic fabrics. Two kinds of Bacteria; Gram-positive and Gram-negative, were used. TEM observation of silver nanoparticles showed their shape, and size distribution. The particles were very small (2-5 nm) and had narrow distribution. SEM images of treated fabrics indicated silver nanoparticles were well dispersed on the surfaces of specimens. WAXS patterns did not show any peak of silver as the fabric had very small quantity of silver particles. However, ICP-MS informed the residual concentration of silver particles on fabrics before/after laundering. The antibacterial treatment of the textile fabrics was easily achieved by padding them with nanosized silver colloidal solution. The antibacterial efficacy of the fabrics was maintained after many times laundering. (C) 2003 Kluwer Academic Publishers.