The paper describes an experimental investigation of regular open-cell cellular structures, where the influence of cell shape on cellular structure behavior under uniaxial compressive loading has been studied. Cellular structures with circular and quadratic cells have been manufactured with the laser sintered rapid prototyping technique using polyamide PA-12 as the base material. An advanced approach for Poisson’s ratio evaluation is proposed, which is based on the three-dimensional laser scanning technique. The experimental results have shown that the same layer-wise collapse mechanism, commonly observed in irregular open-cell structures, can be observed also in regular open-cell structures. The energy absorption characteristics show advantageous performance of cellular structures with circular cells in comparison to the quadratic cells.