We report in this paper analytical results on the optimal design of two-dimensional all metallic sandwiches having lightweight cellular cores subjected to laminar forced convection at fixed pumping power. Various types of core topology are exploited, such as square cells and equilateral triangular cells. The intersection-of-asymptotes method is employed for the optimal design, whilst the fin analogy model is used to account for the contribution of solid conduction. To check the validity and accuracy of the analytical model, the predictions are compared with those obtained using the method of computational fluid dynamics (CFD). The structural parameters of the sandwich optimized include overall length and cell size, with the latter dependent upon porosity and the number of cells along sandwich height. The parameters that may influence the optimally designed sandwich structure are discussed, including overall structural dimensions, pumping power, solid conductivity, and coolant properties. Crown Copyright (C) 2006 Published by Elsevier Ltd. All rights reserved.