Sandwich composites are frequently used in the fields of air, marine, mobile vehicles and construction industry due to their high strength-to-weight and stiffness-to-weight ratios. In addition to these important advantages, sandwich composites and fiber reinforced composites are very sensitive to bending and compression loads. Honeycomb core sandwich structures are preferred in many areas due to their high strength and lightweight. The thickness of the surface plates and core structures, the surface preparation of the layers before bonding are important criteria to increase the strength of the sandwich structure. In this study, a polypropylene honeycomb core sandwich structure was prepared. This structure can especially be used as a panel material by reinforcing with polyurethane and nano level additives. In engineering structures, unexpected damages may occur against any external impact, especially during manufacturing, assembly and use. These damages can be predicted by flexural and compression tests. In this study, the flexural and compression behaviors of sandwich structures are investigated experimentally.