The present work highlights the high efficiency of silver nano-particles deposited over carbon covered alumina (CCA), by electro-chemical deposition method over impregnation method, in controlling microorganisms in water. The anti-microbial activities of the catalysts are determined quantitatively by serial dilution followed by inoculation method. The catalytic characterization of these materials obtained by using transmission electron microscopy (TEM), X-ray diffraction (XRD) and temperature programmed reduction (TPR). TEM and X-ray line broadening technique results indicate the presence of Ag particles in nanometer size. The main advantage of Ag supported catalysts prepared by electro-chemical deposition over that made by conventional impregnation technique is that only small amount is needed and no pretreatment conditions like reduction are required for deactivation of microorganism in water. Thus, silver catalysts prepared by this method are not only efficient but also economical in restoring hydrogen economy. The combined characteristics of Al2O3 and carbon like low acidity, high mechanical strength and presence of meso pores in CCA are also helpful for getting good activity. (c) 2007 Published by Elsevier B.V.