This text focuses on the complications following bariatric surgery. The focus is on the immediate and long term complications that would be important to both the general surgeon and those surgeons with specialty experience in bariatric surgery. Sections address the nutritional deficiencies following bariatric surgery with specific attention to Roux en Y gastric bypass and pancreatico-biliary diversion as well as the correction of these deficiencies with medical intervention as well as the indications for surgical revision or reversal. The text reviews the work-up of a bariatric patient with abdominal pain including the appropriate imaging and threshold for operative intervention and the techniques to achieve optimal visualization during this difficult situation. This section focuses on the operative management of anastomotic and staple line leaks and how to definitively manage these surgical emergencies as well as achieve source control and stabilization.