The adsorption of E. coli onto activated carbon fibers (ACF)(Ag) samples with different initial specific surface areas and Ag contents was investigated. The supporting Ag led to a sharp decrease in specific surface area and a change in bacterial distribution on the surface of ACF. The bacterial adsorption proved to be the more complex process influenced by various factors. Results also showed adverse effects of the Ag particles on the biological activities of the bacteria which might cause inhibitory adsorption onto ACF(Ag).