We attempted to characterize the signs and symptoms of patients presenting with scoliosis as a manifestation of occult syringomyelia, and to determine the effect of syrinx decompression on the deformity and neurologic deficits. This study represented 21 patients treated from 1981 through 1991 at the authors' institution. All patients with occult syringomyelia and no other central nervous system lesions underwent decompression of the syrinx, with improvement in neurologic signs and symptoms. Three of the four with scoliosis that were not treated by arthrodesis showed improvement of their deformity at an average follow-up of 35 months. Three of five patients with myelodysplasia, occult syringomyelia, and scoliosis not previously treated with spinal arthrodesis showed stabilization or improvement of their deformity at an average follow-up of 21 months. We conclude that syringomyelia is associated with a high incidence of developmental scoliosis, and that decompression of the syrinx leads to improvement in, or stabilization of, the majority of scoliotic curves, or postpones the need for fusion.