Superior mesenteric artery syndrome (SMAS) is a rare complication following correction of scoliosis with either nonoperative or operative methods. If the patient diagnosed with this syndrome is not managed timely and adequately, mortality may result. We report two cases of SMAS complicating staged corrective surgery for scoliosis using modern segmental derotation instrumentation system. The aim of this report is to highlight the clinical presentations, laboratory findings, radiologic features, and management of the syndrome. The first patient had the syndrome after two-staged scoliosis surgery with halo traction between two stages, and the second patient after three-staged scoliosis surgery with halo traction between the first and second surgeries. The first patient responded well to conservative treatment. However, the second patient failed to respond to conservative treatment and needed a gastrojejunostomy operation to bypass the duodenal obstruction. Clinicians treating post scoliosis surgery patients should always have a high index of suspicion for this potential life-threatening condition. Early diagnosis will enable a multidisciplinary team approach to be initiated early to provide optimal care for the patient. Nutritional and fluid supplementation is mandatory during conservative treatment. The duration for trial of conservative treatment should not exceed 1 week. [J Formos Med Assoc 2007;106(2 Suppl):S37-S45]