Objective: Postoperative intensive care unit (ICU) admission might be required in adolescent patients following posterior fusion and instrumentation surgery for the treatment of scoliosis. We aimed to evaluate the predictive factors for mechanical ventilation and the characteristics of the patients who required an ICU stay following spinal surgery. Methods: We retrospectively reviewed the records of 85 children undergoing primary scoliosis surgery at a university-affiliated general hospital from January 2010 and June 2020 by the same spinal surgeon. The demographic data, pre- and peritoperative variables were collected and recorded. All patients underwent surgery with a combined anesthesia protocol of fentanyl and remifentanil. Results: There were 31 males (36.5%) and 54 females (63.5%). In the postoperative period, 13 patients (15.3%) were admitted to the ICU, and six of them required mechanical ventilation. Among these, three patients (50%) were extubated within the postoperative 0-12 hours, two (33.3%) within postoperative 12-24 hours, and one (16.7) after postoperative 24 hours. The major complications included acidosis (4.7%), hemodynamic instability (1.2%), hypercapnia (1.2%), hypoxemia (1.2%), and delayed extubation (1.2%). Conclusions: A smaller bodyweight percentile, neuromuscular etiology, abnormal findings in preoperative chest X-ray, additional comorbidities, and preoperative estimated risk for postoperative mechanical ventilation were among the risk factors for postoperative ICU stay. The age, height, weight, degree of the curvature, and the number of operated segments did not have an association with the postoperative outcomes.