Studies that evaluate the predictors and causes of unplanned re-operation in outpatient plastic surgery. This study retrospectively reviewed the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) and identified all plastic surgery outpatient cases performed in 2011. Multiple logistic regression analysis was utilised to identify independent risk factors and causes of unplanned reoperations. Of the 6749 outpatient plastic surgery cases identified, there were 125 (1.9%) unplanned re-operations (UR). Regression analysis demonstrated that body mass index (BMI, OR = 1.041, 95% CI = 1.019-1.065), preoperative open wound/wound infection (OR = 3.498, 95% CI = 1.593-7.678), American Society of Anesthesiologists (ASA) class 3 (OR = 2.235, 95% CI = 1.048-4.765), and total work relative value units (RVU, OR = 1.014, 95% CI = 1.005-1.024) were significantly predictive of UR. Additionally, the presence of any complication was significantly associated with UR (OR = 15.065, 95% CI = 5.705-39.781). In an era of outcomes-driven medicine, unplanned re-operation is a critical quality indicator for ambulatory plastic surgery facilities. The identified risk factors will aid in surgical planning and risk adjustment.