The present paper aims to study the cylindrical section of a Type 3 high-pressure hydrogen storage vessel, combining an aluminium liner which prevents gas diffusion and an overwrapped composite devoted to reinforce the structure. Today, this technique is widely used but still requires consistent time investments whenever a competitive solution, involving to definitely increase weight efficiency, is needed. The laminate composite is assumed to be an elasto-damage material whereas the liner behaves as an elasto-plastic material. Based on the classical laminate theory and on Hill's criterion to take into account the anisotropic plastic flow of the liner, the model provides an exact solution for stresses and strains on the cylindrical section of the vessel under thermomechanical static loading. Part I focuses on the theoretical background. The effect of the stacking sequence on the gap occurrence, on the residual stress magnitude and on the structure stiffness may then be investigated. This will be done and be compared with results of experiments which are carried out on prototypes in the second part of this paper before an optimization is performed. (c) 2005 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.