Integral equation (IE) formulations.solved by the Method of Moments (MoM) have been used successfully to address a vast variety of electromagnetic problems. Printed circuits embedded partially or totally in laterally bounded multilayered media,such as microwave filters or planar antennas and their associated distribution networks are most efficiently treated by this technique. In the case that the structure as well as the excitation hold some symmetry requirements, simplifications may he applied on the problem leading to a considerable improvement in the reduction of computational time and the usage of resources. In this article, we have developed formulations providing theoretical background for applying different types of symmetry conditions in the framework of the MoM-based IE technique applied to printed circuits embedded in shielded multilayered media fed by coaxial lines. Additionally, a comprehensive convergence study has been performed to analyze the effect of mesh resolution and different aspectratios of the rectangular shield on the convergence rate of modal series representing the elements of the MoM matrix. Benefits of applying symmetry simplifications have been pointed out as well. (C) 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 221-226, 2010; Published online in Wiley InterScience (www.interscience.wiley.coin). DOI 10.1002/mop.24868