BackgroundIntraoperative leak test (IOLT) is commonly performed to evaluate the integrity of an anastomosis or staple line during bariatric surgery. However, the utility of IOLT is controversial. ObjectiveTo evaluate the effect of IOLT on postoperative leak-related outcomes after primary bariatric surgery. SettingMetabolic and Bariatric Surgery Accreditation and Quality Improvement Program–accredited centers. MethodsThe 2015 and 2016 Metabolic and Bariatric Surgery Accreditation and Quality Improvement databases were analyzed for sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), and biliopancreatic diversion with duodenal switch (BPDDS) to determine the postoperative anastomotic/staple line leak (A/SL) and leak-related outcomes. ResultsData for a total of 265,309 patients who underwent SG (69.6%), RYGB (29.7%), or BPDDS (.8%) were analyzed. IOLT was performed in 81.9% of all patients. Overall A/SL, mortality rate in patients with leakage, and 30-day leak-related mortality were .28%, .1%, and .003%, respectively. There were no significant differences between the IOLT and non-IOLT groups in terms of A/SL, 30-day mortality in patients with leakage, 30-day leak-related mortality, readmission, reoperation, intervention, or organ/space surgical site infection. However, the rate of 30-day leak-related intervention in BPDDS was significantly lower in the IOLT group compared to the non-IOLT group (.18% versus 1.15%, P = .01). Whether IOLT was performed endoscopically or nonendoscopically had no effect on the rate of postoperative leaks. Overall mean operative time increased by 19.1 minutes (9.5, 11.9, and 21.2 min for SG, RYGB, and BPDDS, respectively) when IOLT was performed. ConclusionThe overall rate of postoperative A/SL and leak-related morbidity was low. This study provided no evidence of either benefit or harm from IOLT in patients who underwent SG, RYGB, or BPDDS.