The ZnO nanowires doped with Mg (Mg-ZnONWs) were produced by thermally oxidizing Zn and Mg powders. TEM and XRD patterns indicated that Mg-ZnONWs were crystalline with a wurzite structure. The Mg doping was confirmed with XPS measurements. The green emission band at 500 nm in the photoluminescence spectrum of Mg-ZnONWs and peaks at 366 nm in low intensity were observable. Raman spectrum indicated that oxygen deficiency was not the dominant factor for the green emission. The green emission was further directly observed with a digital camera.