Background We assessed the clinical features and outcome of morbidly obese patients admitted to the intensive care unit (ICU) for management of postoperative peritonitis (POP) following bariatric surgery (BS). Methods In a prospective, observational, surgical ICU cohort, we compared the clinical features, empiric antibiotic therapy, and prognosis of BS patients with those developing POP after conventional surgery (cPOP). Results Overall, 49 BS patients were compared to 134 cPOP patients. BS patients were younger (45 ± 10 versus 63 ± 16 years; p