Development of a multidisciplinary design optimization (MDO) of a large scale hybrid composite wind turbine blade is performed. Multiple objectives are considered in the MDO process to maximize annual energy production and lifetime profit, minimize weight and power production rate. A wind turbine blade is divided into regions and the layup sequences for each region are considered as design variables. The scale of wind turbine blade is also considered to find the optimum size of a wind turbine blade. Applied loads due to extreme wind conditions for rotor rotation and rotor stop condition are considered for finite element analysis (FEA) to evaluate the structural strength. The designed structural strength and stiffness are demonstrated to withstand the loads due to harmonic excitation from rotor rotation. An MDO process for obtaining an optimum hybrid composite laminate layup and an optimum length of a wind turbine blade is developed and illustrated in this research. The finite element (FE) model and cost estimation model are calibrated and the developed MDO process is verified for an optimum design. The optimum hybrid composite layup sequence and size of a large scale wind turbine blade are highlighted in this research