The feasibility of laser repair was studied based on single-/two-layer multi-bead cladding using a continuous wave (CW) 4 kW Nd:YAG laser system and 1.6-mm EZ33A-T5 filler rods for 22.5-mm ZE41A-T5 magnesium alloy sand castings in the machined surface conditions. The results demonstrate the potentiality of repairing magnesium castings using laser surface cladding by wire. Similarly to weld joints, three distinct regions, i.e. clad, partially melted and heat affected zones are observed in the laser-clad beads. The microstructures in these zones and their evolutions are discussed in details.