This paper deals with buckling load optimization of symmetrically laminated composite thin plates under the uniaxial and biaxial compressive loads with discontinuities along the boundaries. The objective of the design problem is to maximize the buckling load of the laminated plates and the fibre orientation is taken as design variable. The classical laminate plate theory is used for the mathematical formulations of the laminates. The modified feasible direction method is used as optimization routine. Therefore a program based on FORTRAN is used. Finally, the effect of nonuniform boundary conditions, aspect ratios and load ratios on the optimum results is illustrated. (C) 2008 Elsevier Ltd. All rights reserved.