Au/TiO 2 catalysts were prepared by deposition–precipitation method using various bases such as NaOH, NH 4 OH and urea. The catalysts were characterized by ICP-MS, XRD, TEM and XPS. The catalytic activity of these catalysts has been investigated for preferential oxidation of carbon monoxide in hydrogen stream. A high gold dispersion and narrow size distribution was obtained for Au/TiO 2 catalysts by using different precipitating reagents, such as NaOH, NH 4 OH and urea. Au/TiO 2 catalyst prepared by using NaOH as base agent shows higher deposition of gold on the TiO 2 support when compared with other base agents. The uptake of gold on TiO 2 decreased as the pH value increased from 5 to 9. The catalytic activity of CO oxidation increases as the metal loading increases and CO selectivity decreased with increasing reaction temperature on all catalysts. Au/TiO 2 catalyst prepared by using NaOH as the base agent at low pH ∼6 is found to be the better catalyst, henceforth the catalytic activity is found to be higher for preferential oxidation of CO in H 2 stream at 80°C.