This research investigates the oxidation behaviours of an additively manufactured (AM) superalloy Inconel 718 and to compare its oxidation performance to that of wrought Inconel 718. A plasma arc additive manufacturing process was utilized to manufacture the AM samples. All samples were exposed at 800°C and 900°C. The oxidized samples were analysed using SEM and EDS. Both surface and cross-section microstructure were examined, in addition to microstructure changes in the substrate. The results showed the two alloys had similar weight changes up to 400 hours. The thickness of the chromia oxide scale formed on AM Inconel 718 was thinner than on the wrought samples. There was also more internal oxidation on the AM samples. In addition, the formation of a subscale Nb-rich layer was observed between outer chromia and substrate. Based on the preliminary results, it was concluded that the AM material had slightly inferior oxidation performance than wrought alloy.