Locomotor training using treadmill has been shown to elicit significant improvements in locomotor ability for some children with cerebral palsy (CP), the functional gains are relatively small and it requires greater involvement from a physical therapist. Current robotic gait training systems are effective in reducing the strenuous work of a physical therapist during locomotor training, but are less effective in improving locomotor function in some children with CP due to the limitations of the systems. Thus, a 3D cable-driven robotic gait training system was developed and tested in five children with CP through a 6 week of long-term gait training. Results indicated that both overground walking speed and 6 minute walking distance improved after robot assisted treadmill training through the cable-driven robotic system, and partially retained at 8 weeks after the end of training. Results from this pilot study indicated that it seems feasible to conduct locomotor training in children with CP through the 3D cable-driven robotic system.