Accelerated discharge protocols for scoliosis surgery have recently been described in the literature. There are limited data describing the association of length of stay (LOS) during the index admission with postoperative outcomes. We sought to define the economic and clinical implications of an additional 1 day in the hospital for scoliosis surgery. The Statewide Planning and Research Cooperative System database was used to identify patients with adolescent idiopathic scoliosis who underwent spinal fusion from 1 October 2007 to 30 September 2012 at high-volume institutions (>20 cases/year) in the state of New York. Regression models were adjusted for age, sex, race, insurance, comorbidity score, and perioperative complications during the index admission. Among the 1286 patients with AIS who underwent spinal fusion, the mean LOS was 4.90 days [95% confidence interval (CI)=4.84-4.97; SD=1.19]. In the perioperative period, 605 (47.05%) underwent transfusion and 202 (15.71%) had problems with pain control. An additional 1 day in the hospital was associated with $11 033 (95% CI=7162-14 904; P<0.001) in insurance charges, $5198 (95% CI=4144-6252; P<0.001) in hospital costs, 28% increased risk (odds ratio=1.28; 95% CI=1.01-1.63; P=0.041) of all-cause 90-day readmission, and a 57% increased risk (odds ratio=1.57; 95% CI=1.13-2.17; P=0.007) of returning to the operating room within 90 days. Increased LOS during the index admission scoliosis surgery is associated with higher costs and an increased risk of 90-day postoperative complications. Protocols to decrease LOS for this surgery have potential benefits to patients, hospitals, and insurers. Level of Evidence: Level III, retrospective comparative study.