Mechanical properties similar to natural bone and good biocompatibility make magnesium a great option for its use as biodegradable implant material. The use of castings as fabrication technique brings inherent problems, such as segregation and void formation. Also, the architecture of the specimens created by using these techniques is limited. This study shows the implementation of WAAM for the fabrication of elements made out of AZ91D magnesium alloy (9% aluminium and 1% zinc). The results demonstrate that porosity or cracking only appears at the surface of the individual printed lines, while the central sections presents a void-less structure composed by an HCP magnesium matrix and a high density of well dispersed aluminium-zinc rich precipitates. EDS mapping confirms the presence of orthorhombic Al5Mg11Zn4 phase. Also, the relationship between the heat present in the system and the morphology of the lines is analysed.