This research's pioneering aim is to address the preparation of Cu and Cu/Zn nanocatalysts supported on alumina using microemulsion route. To do so, stable colloidal systems of Cu and Zn nanoparticles were rstly prepared in a W/O microemulsion system. The formulated microemulsions were formed from copper nitrate and zinc nitrate as a source of metals, cyclohexane as oil phase, and AOT as an anionic surfactant. To con rm the formation of Cu and Zn colloidal systems after ions reduction, Dynamic Light Scattering (DLS) method was used. From the DLS results, it was found that the nanoparticles' average size for colloidal suspension system was about 2 nm. Finally, -Al2O3 was added to the colloidal systems to make Cu/Al2O3 or Cu-Zn/Al2O3 nanocatalysts. The resulted nanocatalysts were characterized by FE-SEM and XRD techniques. The prepared nanocatalysts were tested for hydrogenation reaction of an unsaturated aldehyde in a batch reactor and mild condition