BACKGROUND: The purpose of this study was to demonstrate the relationship between the surgical approach employed for adults undergoing bariatric surgery for obesity in New York State and in-hospital postoperative complications. Understanding the differences among surgical approaches in terms of the type, extent, and likelihood of postoperative complications and the patient characteristics associated with them, particularly as the annual volume of bariatric surgery increases, can inform decisions about the appropriate bariatric surgical approach for patients with particular characteristics. METHODS: Using New York's inpatient hospital discharge database, we identified 8,413 adults who underwent a bariatric surgical procedure during calendar year 2006. The three most common bariatric surgical approaches were identified, postoperative complication rates and descriptive statistics for the demographic characteristics and comorbidities for patients of each surgical approach were generated, and a logistic regression model was constructed to predict the likelihood of postoperative complications. RESULTS: Of all bariatric surgical patients, 8.1% experienced a postoperative complication, but complication rates varied dramatically across the surgical approaches, with open bypass patients having the highest complication rate and laparoscopic banding patients having the lowest rate. Different complications were associated with the three surgical approaches, as were the various patient demographic characteristics and comorbidities. The multivariate logistic regression indicated that open bypass patients were 5.4 times and laparoscopic bypass patients were 3.2 times more likely to experience a complication compared to laparoscopic banding patients. CONCLUSION: Analyses of bariatric postoperative surgical complications must take into account the surgical approach employed.