One option available to persons with severe mobility limitations is body weight supported treadmill training. Indeed, this rehabilitation approach has been utilized with some success in various clinical populations, such as stroke and spinal cord injury, and is believed to target neuroplasticity. Specific to persons with MS, body weight supported treadmill training has shown great promise in improving quality of life, symptoms and functional mobility in two small (n=4 and n=6) pilot investigations. However, previous research has been hampered by methodological limitations including small sample size, lack of a control group and limited training sessions. Consequently, no firm conclusion regarding the benefit of body weighted supported treadmill training in persons with MS can be drawn. The proposed project seeks to determine if twenty-weeks of body weight supported treadmill training leads to improvements in physiological function, mobility and quality of life in persons with MS with severe mobility limitations. The outcomes of this project have the potential to lead to new rehabilitation approaches capable of improving function and quality of life in persons with advanced MS.