A novel and versatile optimum-cost design approach that embraces the ideology of concurrent engineering is described. The approach is incorporated into optimum-design software to permit the determination of the least-cost design for prismatic assemblies of laminated composite plates, which occur in advanced aerospace construction. Comparisons between cost and mass optimum designs of different panel topologies for two proposed manufacturing processes are presented. The different panel topologies were obtained by varying the number of stiffeners and by using either blade or T stiffeners. In total, 40 different panels were optimized separately for manufacturing cost, mass, and total cost, i.e., including running costs. The running costs were included by associating a penalty function with the mass of the panels. The results show that the approach is extremely versatile and enables different topologies and manufacturing processes to be compared in detail.