Abstract: A powered gait orthosis is provided for exercising the legs of a patient, and includes a treadmill for acting on the feet of the patient and a pair of gait simulation assemblies disposed adjacent to the treadmill. Each gait simulation assembly includes a support arm including pivotally movable first and second depending arms, which further include drive means for movement thereof about first and second horizontal axis. The device further includes first and second attachment means on the first and second depending arms, for attachment to a patient's thigh and ankle, respectively. A lifting means including a drive means is supported in a vertically extending tower, which houses a gait simulation assembly. The lifting means lifts and holds a patient on the treadmill. Control means is provided to operate the depending arms in a controlled manner to cause the legs of the patient to move in a desired gait.