Density functional theory has been employed in order to investigate the structure and stability of Si@Al12Hn ( ) clusters. Hydrogenated Si@Al12 clusters exhibit pronounced stability for even numbers of H atoms. Large binding energy, HOMO-LUMO gaps and increased ionization potentials imply that these clusters should be physically and chemically stable. The analysis of the charge density of the HOMO plot illustrates that a pair of hydrogen atoms prefer to occupy opposing on-top sites for clusters with an even n number. Studies of deformation charge density plots demonstrate that significant charge transfer occurs from the Si@Al12 to the H atoms.