Proprioception testing and gait analysis was performed on a group of 17 patients with Idiopathic scoliosis. All curves had documented progression. The average curve was 26.8°, all primary curves being right thoracic. The average age was 14.8 years. Twelve, healthy, age-matched controls underwent identical testing. Results showed that scoliotic subjects had asymmetry in their ability to reproduce angles between their two knees, as well as an absolute deficit in their ability to reproduce angles as compared with controls (P<0.01). The threshold of detection of change in angle at the knee was also quantitatively higher than controls (P<0.05), although asymmetry was not statistically significant. No significant differences were measured in gait parameters between scoliotics and controls. These joint position tests have been applied previously to young and elderly adults, athletes, and total joint patients. In no group has any asymmetry of response been demonstrated, both extremities showing virtually identical performance in each case. The tests administered measure sensory modalities, which are conducted through the posterior columns. Although the site of damage in the neural pathway cannot be specifically localized by these tests, results of this study support the presence of a neurologic deficit in idiopathic scoliosis.