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The application of composite cylindrical shell is greatly increased in aerospace and marine structures. The present paper investigates the stability analysis of ring- stiffened cylinders. Incorporating pre-buckling deformation, buckling load is calculated through geometrically non-linear analysis. The cinematic relations of shell, based on Sanders non-linear theory by including first order shear deformation (FOSD) are manipulated. The appropriate t:raditional Fourier series functions are selected to express the corresponding displacements and rotations of cylindrical shell and ring stiffeners. The shell is subjected to both axial and external pressure. The study is based on Ritz method and the load-deflection and load-interaction forces curves are obtained by mixed Newton-Raphson iteration and arc- length method. The results are presented in terms of buckling and post-buckling response for different shell and stiffeners lay-ups. Also the effect of stiffened shell stacking sequences on interaction forces is investigated.