A finite element-based shape optimization program has been developed for three-dimensional shell structures and the shape optimization of shell structures has been performed. The shape optimization program is implemented by a job control language and a reliable finite element package program, ANSYS, is used for structural analysis. To achieve the shape optimization, different principles such as structural analysis, automatic mesh generation, sensitivity analysis and mathematical programming are inter-related. The objective is to minimize the weight of the shell structure under constraints that are the maximum value of the von Mises stress in each element and the move limit for each design variable. The design sensitivities are calculated using the finite difference method. The search for the final shape of a structure is performed using the linear programming technique. Several examples are provided. (c) 2006 Elsevier Ltd. All rights reserved.