the present paper outlines the large deflection elasto-plastic analytical results for thin square plates with initial imperfections subjected to in-plane loads. The elasto-plastic rigidities are calculated using a rigorous multi-layer approach. The governing equations are solved in an incremental form by applying dynamic relaxation method (DRM) as proposed by the author M, 21. based on the computational results, the paper discusses the plastici zation history of the panels.