Diffusion couple experiments for Mg–Al and Mg–Zn systems with polycrystalline Mg were performed between 638 and 693 K (365 and 420 °C) and 553 and 593 K (280 and 320 °C), respectively, to determine the diffusion of Al and Zn in Mg crystal depending on the orientation of basal plane of hcp Mg. Solute (Al and Zn) diffusion coefficient decreases elliptically in Mg crystal from the basal plane towards normal to the basal plane.