Postural equilibrium factors were evaluated as indicators of the prognosis in 52 patients with adolescent idiopathic scoliosis. The hypothesis was that dysfunction in these equilibrium factors might imply a higher risk for the curve to progress. The postural equilibrium was studied by stabilometry, and the function of the central nervous system was assessed by electoencephalography (EEG) and the vestibular function by electronystomography (ENG). During a follow-up period averaging 2.9 years, ten patients showed progression of the scoliosis. No differences were found in the distribution and frequency of abnormalities between the patients with progressive and nonprogressive scoliosis. Stabilometry, electroencephalography, and electronystomography as used in this study did not seem to be of predictive value for the outcome in the individual case.