A simultaneous optimization methodology is proposed considering both the structural and the process requirements for the weight minimization of laminated plates manufactured by the Resin Transfer Molding (RTM) process. The coupling between the structural performance and the process cost is considered through the investigation of state parameters in the RTM process. As the structural constraint, maximum allowable displacement or maximum allowable failure index of the structure under load is assigned. For the process constraint, maximum allowable mold filling time is given. A new approach to deal with design constraints without having to concern about the penalty parameters is suggested. The influence of design constraints on the optimal design configuration is investigated through parametric studies. As the optimization scheme, Genetic Algorithm (GA) is employed. To take into account the layer number variation, genetic operators such as the crossover and the mutation are modified.