This paper describes the design and integration of three joint torque sensors on the arm of the iCub platform [1], [2]. The objective is to enhance the robot arm with joint torque control capability. This activity is part of a general upgrade of the humanoid robot to provide the its 53 degrees of freedom low-level joint torque control capabilities. In particular, the shoulder joint is challenging because of its complex and compact mechanical structure. We first modeled the behaviour of the sensors with analytical equations and the sensor geometry were subsequently optimized using finite element structural simulations. The sensors were then constructed, and integrated in the arm assembly. Finally we present preliminary experiments to validate the design.