In this work, a characterization in terms of structural, microstructural and mechanical properties of Inconel 718 alloy has been performed, with a comparative study between as-built and heat treated samples, including the case study of lattice structures. All samples have been produced via Additive Manufacturing. The work was aimed at: 1) investigating the structural, microstructural and mechanical properties of bulk samples, before and after the heat treatment; 2) studying the structural, microstructural and mechanical properties of three different lattice structures, before and after the heat treatment. In both as-built bulk and lattice structures, melt pools on xy plane were elongated following the scanning direction, while on xz plane they assumed an arc shape due to the presence of a thermal gradient. Overall, a fine cellular/dendritic microstructure, due to high thermal gradient and intermediate interfacial solidification rate was observed, constituted by the strengthening γ’/γ’’ phases, with equiaxed and elongated grains on xy and xz planes, respectively. From Vickers hardness tests, comparable average values of hardness were obtained in bulk samples and lattice structures. Concerning compressive behaviour, the stress-strain curves of structures A and C showed a stress plateau, suggesting a bending dominated behaviour, while structure B did not show such a feature and revealed larger values of elastic modulus and yield stress as consequence of its higher density. After the heat treatment (solution annealing - ageing at 720 °C - ageing at 620 °C), the microstructure showed inside the grains, some fine γ’/ γ’’ precipitates dispersed in the γ matrix, while along the grain boundaries coarser precipitates continuously distributed. From EBSD analyses, these can be attributed to both δ and Laves phases, which caused an overall embrittlement. From Vickers hardness tests, it turned out that the average hardness values were higher than those of as-built samples and the standard deviation was smaller, probably correlated to a homogenization after the heat treatment. The elastic modulus almost doubled for all the structures, while for lattice A and B the behaviour in the plastic regime showed small fluctuation, probably referred to the rupture of the struts of the lattice structures.