Magnesia-supported Sn-Pt catalysts were prepared by reaction between preformed platinum metal particles and Sn(n-C4H9)(4). HRTEM and H-2-chemisorption data confirm the synthesis of very small tin-decorated platinum particles (similar to 1.0 nm mean diameter), Preliminary studies on catalytic hydrogenation of citral in a trickle-bed reactor reveal that 97% selectivity to unsaturated alcohols at 100% conversion can be easily achieved. The electronic ligand effect produced by the basic support is supposed to be fundamental to enhance the selectivity to unsaturated alcohols and to stabilise the bimetallic particles,