Background: Biliopancreatic diversion with duodenal switch (DS) is known to be superior in weight loss to other bariatric procedures, but with the disadvantage of increased complication rates, Single-anastomosis duodenal-ileal bypass (SADI-S) is reported to have similar weight loss with lower complication rates compared with traditional DS. Objectives: The aim of this study was to compare weight loss and complication rate between SARI-S and double-anastomosis DS at a single institution. Setting: Academic hospital, United States. Methods: A retrospective chart review was performed on 185 patients who underwent laparoscopic or robot-assisted laparoscopic DS between March 1, 2015 and December 10, 2017. A total of 11 l patients had SADI-S, and 74 patients underwent double-anastomosis DS. Results: Baseline patient characteristics were comparable between the 2 groups. The mean preoperative body mass index was 56.3 kg/m(2) and 54.4 kg/m(2) in SADI-S and double-anastomosis DS patients, respectively. Thirteen (11.7%) and 4 (5.4%) patients were readmitted within 30 days after SADI-S and double-anastomosis DS, respectively (P = .16). Percentage of total weight loss was 22.0%, 38.5%, and 44.2% in the SADI-S group and 20.2%, 38,0%, and 48.4% in the doubleanastomosis DS group at 6, 12, and 24 months, respectively. The majority of patients had vitamin A and E levels in the normal range. However, 40% to 60% of the patients had low levels of vitamin D after the procedure. Conclusions: SADI-S and double-anastomosis DS are comparable in terms of weight loss and complication rate. However, close nutritional follow-up is warranted for both procedures. (C) 2018 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.