In this report we describe a young woman with idiopathic thoracic scoliosis associated with marked lordosis. Pulmonary function, tested in the upright standing position, showed a restrictive pattern of impairment. However, when the patient was tested in the forward-flexed position, pulmonary function was dramatically improved. Following surgical partial correction of the thoracic deformity, pulmonary function was largely within normal limits. Our report emphasizes the detrimental effects of thoracic lordosis on pulmonary function. In addition, our patient demonstrated marked position dependence of pulmonary function, a feature not previously described in patients with deformations of the thoracic spine.