Scoliosis interferes significantly with the functional ability of most children with a myelomeningocele. While it is recognized that tethered cord at the repair site causes neurological deterioration, it has been controversial whether tethered cord causes scoliosis. The spinal cord was untethered in 30 children with progressive loss of function and scoliosis. Of 6 children with curves greater than 50° only 1 improved. Of the other 24 children their curves were stable or improved at 1 year follow-up. At late follow-up, 2–7 years, 63% were stable or improved while 38% began to progress. Tethered cord causes scoliosis and stability or improvement can be anticipated following untethering. Close long-term follow-up is essential to identify those individuals with retethering of their cord.