Acute respiratory failure (ARF) in adults with severe thoracic spinal deformity is said to be a preterminal event with a median survival of one year. Twenty patients with ARF (mean +/- S.D., arterial oxygen tension [PaO2] 35 +/- 7 mm Hg, arterial carbon dioxide tension [PaCO2] 63 +/- 9 mm Hg, pH 7.34 +/- 0.08) due to severe scoliosis or kyphosis (spinal curve 113 +/- 28 degrees ) were seen between 1965 and 1980. All 20 survived the initial episode of ARF and during the follow-up period (median, six years) experienced 2.4 additional episodes of ARF. The age at presentation was 52 years (mean, range 13 to 78), and the cause of spinal deformity was idiopathic (seven patients), poliomyelitis (seven), tuberculosis (five), and arthrogryposis multiplex congenita (one). ARF was treated with controlled low dose oxygen by Venturi mask and intensive general measures in 13 patients and by mechanical ventilation in seven. Of the latter seven patients, ventilatory failure was treated in two with a tank respirator and a cuirass, avoiding endotracheal intubation. Outpatient management was similar to conventional therapy for chronic obstructive pulmonary disease (COPD). Severe restrictive ventilatory impairment characterized the group after recovery from the first episode of ARF: vital capacity (VC) 906 +/- 362 ml (31 percent predicted) and FEV1 589 +/- 197 ml (23 percent). During follow-up, the VC decreased by 1.5 ml/year and the FEV1 by 13.9 ml/year. The PaO2 increased by 2.6 mm Hg/year and the PaCO2 increased by 1.7 mm Hg/year. Successful management of ARF due to severe scoliosis or kyphosis is possible in the great majority of patients, and long-term survival may be expected. Unlike COPD, pulmonary function following ARF in kyphosis or scoliosis deteriorates at a slower than expected rate and, in fact, may improve with treatment over many years.