A method is presented for the minimum weight design of laminated composite plates under inplane loading conditions subject to strength and stability constraints. A computer program has been developed to carry out this procedure. The thicknesses of groups of layers and a critical fibre orientation are taken to be design variables. A two-stage optimization method is used: For the fibre orientation a discrete line search technique is used such that the constraints are satisfied with the smallest number of layers. For the thicknesses a modified feasible direction method is used. The strength criterion employed is the Tsai-Wu tensor theory. Several numerical examples are presented to demonstrate the effectiveness of optimization procedure presented and the results are compared with those of the quasi-isotropic material.