This paper describes the development of a gait rehabilitation system with a locomotion interface (LI) for training patients to climb stairs. The LI consists of two 2-DOF manipulators equipped with footpads. These can move the patient's feet while his or her body remains stationary. The footpads follow the prerecorded motion of the feet of healthy individuals. For gait training, the patient progresses sequentially through successively more advanced modes. In this study, two modes, the enforced climbing of stairs and interactive climbing of stairs, were developed. In the interactive mode, foot pressure sensors are used to realize interactive walking. Comparisons were made between the modes for healthy individuals and a patient. The effectiveness of the system was examined using electromyography (EMG) and foot pressure data.