THIS PAPER INVESTIGATES THE ULTIMATE STRENGTH ANALYSIS OF COMPOSITE LAMINATED PLATES UNDER BOTH IN-PLANE COMPRESSIVE AND LATERAL PRESSURE LOADS. THE ANALYSIS IS BASED ON THE FIRST ORDER SHEAR DEFORMATION PLATE THEORY AND THE ASSUMPTION OF SMALL DEFLECTIONS. WITH THESE ASSUMPTIONS, THE OBTAINED RESULTS ARE REASONABLE FOR RELATIVELY THICK PLATES. THE LAMINATES ARE SIMPLY SUPPORTED OUT OF THEIR PLANE AT THE LOADED ENDS AS WELL AS UNLOADED EDGES. THE IN-PLANE LATERAL EXPANSION IS ALLOWED; HOWEVER, THE EDGES ARE KEPT STRAIGHT. THE FORMULATIONS ARE BASED ON THE CONCEPT OF THE PRINCIPLE OF MINIMUM POTENTIAL ENERGY. FOR THE FAILURE ANALYSIS, HASHIN FAILURE CRITERION IS USED AND THE INSTANTANEOUS DEGRADATION OF MATERIAL PROPERTIES IS ASSUMED FOR FAILED PLY OR REGION OF FAILED PLY. INTER LAMINAR FAILURE IS NOT CONSIDERED AND THE OUT OF PLANE SHEAR STIFFNESSES ARE NOT DEGRADED IN THIS STUDY. WHEN FAILURE IS DETECTED IN THE PLATE, TWO DIFFERENT DEGRADATION MODELS HAVE BEEN USED, COMPLETE PLY DEGRADATION MODEL AND PLY REGION DEGRADATION MODEL. A NUMBER OF APPLICATIONS INVOLVING PLATES WITH DIFFERENT MAGNITUDE OF PRESSURE LOADS ARE DESCRIBED TO INVESTIGATE THE CAPABILITY OF METHOD.