This paper presents the design and the development process of a hybrid FES-Exoskeleton (EXOSLIM) system intended for rehabilitation of the upper limbs in stroke patients. The present work is aiming to develop an exoskeleton that supports the human upper limb activities by using a control architecture for shoulder flexion and extension, abduction and adduction, medial and lateral rotation, elbow flexion and extension and forearm pronation and supination. The main goal is to develop an adaptable and modular exerciser, which follows one of the user upper limbs during the rehabilitation process, sparing training time and allowing fast adjustments to new situations and using any residual control of the end-user. These facts make the system suitable for long term utilization in daily activities. The exoskeleton is designed with mechanical compliance to the human arm. The actuation system is also studied and designed. The paper provides an overview of the upper limb rehabilitation and evaluation techniques.