This paper describes a new approach to the design of a lightweight robotic arm for service applications. A major design objective is to achieve a lightweight robot with desired kinematic performance and compliance. This is accomplished by an integrated design optimization approach, where robot kinematics, dynamics, drive-train design and strength analysis by means of finite element analysis (FEA) are generally considered. In this approach, kinematic dimensions, structural dimensions, and the motors and the gearboxes are parameterized as design variables. Constraints are formulated on the basis of kinematic performance, dynamic requirements and structural strength limitations, whereas the main objective is to minimize the weight. The design optimization of a five degree-of-freedom (dof) lightweight arm is demonstrated and the robot development for service application is also presented.