The Ru:Mn/SiO2 supported system with various level of Mn war prepared by co-impregnation method dispersed on high surface area SiO2 support. The system war investigated for CO hydrogenation reaction. The catalytic activity and product selectivities data reveals electronic and ensemble street produced by the addition of Mn to Ru/SiO2 system It is suggested that addition cf Mn produces new surface sites Ru:Mn bimetallics which modify the catalytic behaviour electronically and geometrically.