The main purpose of V-core and I-core sandwich panel optimisation is the development of approximated models, also known as metamodels. They can be used as the fast and reliable reanalysis tool, since application of direct minimization algorithm and multiple finite element analysis is too expensive from a computational point of view. For this reason, the optimisation technique of building metamodels has been developed employing the response surface methodology and design of experiments. Additionally, metamodels used for design optimisation can be implemented for parametrical studies and sensitivity analysis. The resulting design procedure provides an effective optimal design tool that permits optimising any system or process with respect to any objective function. In this particular case we minimize the cost and weight criteria for different core sandwich plates under the bending loading.