Identifying risk factors for adverse events after bariatric surgery (BaS) can help define high-risk groups to improve patient safety. We calculated cumulative incidence of adverse events and identified risk factors for these events using validated surgical patient safety indicators (PSIs) developed by the Agency for Healthcare Research and Quality. BaS patients > or =18 years old were identified using the 2002 Nationwide Inpatient Sample. Cumulative incidence at discharge was calculated for accidental puncture or laceration (APL), pulmonary embolus or deep venous thrombosis (PE/DVT), and postoperative respiratory failure (RF). Factors predictive of these PSIs were identified. From 7,853,982 discharges, a national cohort of 69,490 BaS patients was identified. During BaS hospitalization, the cumulative incidences per 1000 discharges of APL, PE/DVT, and RF were 12.6, 3.4, and 7.3, respectively. Risk factors for APL included male gender (odds ratio [OR] 1.6, 95% confidence interval 1.1-2.3, P < 0.05) and age of 40-49 years (OR 1.6 [1.1-2.3], P < 0.05) compared to ages 18-39 years. Patients aged 50-59 years (OR 3.5 [1.6-7.7], P < 0.05) had a higher chance of PE/DVT compared to those 18-39 years. Male gender (OR 1.8 [1.1-2.9], P < 0.05), ages 40-49 (OR 2.1 [1.1-4.2], P < 0.05) and 50-59 (OR 3.8 [2.1-6.9], P < 0.05), a history of chronic lung disease (OR 1.7 [1.1-2.7], P < 0.05), and Medicare coverage compared to private insurance (OR 2.2 [1.2-3.8], P < 0.05) were predictive of RF. This study established national measures for BaS adverse events. Further, risk factors associated with adverse events varied by gender, age, insurance status, and comorbidity. Evaluation of these higher risk BaS groups is needed to improve patient safety.