Background: Laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic adjustable gastric banding (LAGB) are common surgical procedures for morbid obesity. Few single-institution studies have compared LRYGB and LAGB. Methods: All patients under-went LRYGB or LAGB at Legacy Health System. The data for the study were obtained from a prospectively maintained database. Preoperatively, most patients were allowed to choose between LRYGB and LAGB. Age, gender, body mass index, complications, mortality, and weight loss were examined. Results: From October 2000 to October 2005, 492 patients underwent LRYGB and 406 patients underwent LAGB. The mean age was 44 +/- 10 and 47 +/- 11 years, respectively (P < .001). The mean preoperative body mass index was 49 +/- 8 and 51 +/- 9 kg/m(2) (p < .05). Patients undergoing LRYGB had longer operative times (134 +/- 41 min versus 68 +/- 26 min, P < .001) and longer hospital stays (2.5 +/- 3.5 d versus 1.1 +/- 1.1 d, P < .001). Blood loss was minimal in both groups. The percentage of excess weight loss was significantly better for patients who underwent LRYGB at all points of follow-up, except at 5 years. Total complications occurred in 32% of patients who underwent LRYGB and 24% of patients who underwent LAGB (P = .002). The 90-day mortality rate was .2% in both groups. The reoperation rate was the same (17%) in both groups. Conclusions: Patients undergoing LAGB had shorter operative times and shorter hospital stays compared with patients undergoing LRYGB. LAGB was associated with a lower complication rate. Early weight loss was significantly greater after LRYGB, but the data comparing long-term weight loss after LRYGB and LAGB have been inconclusive. (Surg Obes Relat Dis 2007;3:42-51.) (C) 2007 American Society for Bariatric Surgery. All rights reserved.