Background: Complication rates for laparoscopic bariatric surgery remain in evolution. Methods: Single institution review of the initial year's experience with laparoscopic gastric bypass compared with open gastric bypass complications for the same period. Results: There were 20 laparoscopic and 52 open gastric bypass procedures. Five laparoscopic patients had major complications. There were 4 anastomotic leaks. Nine open bypass patients had major complications, with 2 leaks. Leak rate was 20% for the laparoscopic group and 4% for the open group. All leaks in both groups led to substantial morbidity. There were two deaths, one in each group. The laparoscopic death was from postleak sepsis. Conclusions: Gastric bypass, whether done open or laparoscopically, has significant surgical risk. Complication profiles differed between the two groups. Anastomotic leaks were significantly more frequent in the laparoscopic group, probably related to the learning curve. There is a continued need for open surgery in many bariatric patients. (C) 2002 Excerpta Medica, Inc. All rights reserved.