The large possibilities of design offered by additive manufacturing (AM) has motivated numerous studies for process optimization. AM is particularly interesting for parts with complex shapes and for high-strength materials such as superalloys, which are difficult to machine. However, AM processes are prone to specific processing defects, such as gas porosity and lack of fusion. These defects are detrimental for components bearing fatigue loading because they constitute potential crack initiation sites. In order to investigate the effect of defect location on crack propagation in IN718, fatigue test specimens with artificial defects were processed by laser powder bed fusion (LPBF). Internal defects were introduced directly during material deposition, while surface defects were machined by electro discharge machining (EDM). High cycle fatigue (HCF) tests were carried out at both room temperature and 550 °C. Crack growth was monitored through potential drop technique, tomography for internal defects and high-resolution surface imaging for surface cracks. For both types of artificial defects, fatigue striations were also counted after fracture to get the local fatigue crack growth rate (FCGR). The associated stress intensity factor amplitude ΔK were calculated using the Z-Cracks module in Z-Set. In the case of the surface defect, a strong plasticity effect was observed near the surface as well as a short crack effect. At room temperature, a lower FCGR is observed for internal defects. This indicates that, the defect atmosphere (air for surface defects, argon with traces of oxygen for internal defects) influences the FCGR in LPBF IN718. The same methodology was used at 550°C, showing in this case a stronger effect of the atmosphere. Indeed, for surface defects, the crack propagation is assisted by the oxidation of the material.