Copper, palladium and iridium nanoparticles were synthesised within the pore channels of selectively grafted mesoporous silica SBA-15. The support and catalysts were characterised by different techniques. The synthesized catalyst were able to catalyse oxidation of carbon monoxide with activity values as high as 7.0 x 10(-3) mmol g(-1) cat s(-1) at 353 K. Carbon monoxide conversion was found to increase with decreasing nano particle size.