<p>Shell-infill integrated structures are composed of an exterior solid shell and an interior lattice infill, whose integration provide an optimum balance between resistance and lightweighting. The mechanical responses of lattice structures have already been extensively studied in the literature. However, the integrated response of the shell-lattice structure is yet unclear. This study aims to analyse the synergization between the shell and the lattice structure through compression testing and finite element modelling (FEM), evaluating how different shell thicknesses and strut sizes contribute to the mechanical response of the integrated structures. Shell contribution was compared with that of the strut to examine where the added volume is more effective for resisting compressive loads. The results proved that thinner lattices with thicker shells were more efficient for resisting compression loads, doubling its resistance for the same volume fraction. In addition, the load application direction with respect to the lattice free surface has also been reported to influence the mechanical response of the integrated structures. The results experimentally obtained agree with those obtained by FEM proving that the solid body model used is accurate enough to reproduce the mechanical response of the integrated structures.</p>