Background Adult spine deformity surgery (ASDS) is a significantly invasive procedure with a relatively high complication rate. The thirty-day hospital readmission rate following surgery is an important quality measure monitored by multiple quality reporting agencies. Purpose This study seeks to determine the risk factors for 30- day readmission rate in patients undergoing ASDS and identify the risk factors associated with readmission. Study Design This is a retrospective multicenter study. Methods The National Surgical Quality Improvement Program database, which is a large multi-institutional database, was searched for patients that underwent ASDS from 2011 to 2013. The patients were identified by searching seven Current Procedural Terminology codes most commonly used for spinal deformity surgery. Twenty-seven preoperative variables, including patient demographics and comorbidities, intraoperative parameters, and postoperative complications were analyzed to identify risk factors for readmission. Results A total of 747 adult patients who underwent ASDS were identified. Of the 747 patients, 7.5% (56/747) were readmitted within 30 days. The most common causes of readmission were infection (n=11), hematoma or seroma formation (n=5), and postoperative pain (n=3). Univariate analysis revealed male gender (p=.038, odds ratio [OR]=1.83) and pulmonary embolism before discharge (p=.048, OR=8.44) to be associated with readmission. In multivariate analysis, obesity (p=.047, OR=1.80), peripheral vascular disease (p=.045, OR=17.52), pulmonary embolism before discharge (p=.012, OR=10.35), and total or partial dependent preoperative functional health status (p=.041, OR=2.45), were found to be independent risk factors for readmission. Age, smoking, and resident involvement during surgical procedure were among the many factors not associated with increased risk of readmission. Conclusions The 30-day readmission rate for ASDS is increasingly becoming a significant health-care quality indicator. Patients with the aforementioned significant risk factors should be closely followed up, which can potentially avoid subsequent readmission.