BACKGROUND: The Bariatric Outcomes Longitudinal Database (BOLD) is a registry of self-reported bariatric surgery patient information from the American Society for Metabolic and Bariatric Surgery Bariatric Surgery Center of Excellence participants. The present study was undertaken to define the baseline characteristics of the patients with data entered into BOLD. METHODS: The data submitted by >800 surgeons and >450 facilities using BOLD before May 20, 2009, were analyzed. RESULTS: A total of 57,918 research-consented patients with surgical procedure data were included. Of the 57,918 patients, 41,243 were adults aged 26-55 years, with few patients aged < or =18 years (.14%) or > or = 66 years (5.67%). Females constituted a significant majority of the study population (45,619 [78.76%]). Of the 57,918 patients, 78.12% registered were described as Caucasian, 10.52% as African-American, 6.02% as Hispanic, .20% as Asian, and .46% as Native American. The most common bariatric surgical procedure was some form of gastric bypass (31,668 [54.68%]), followed by some form of gastric banding (22,947 [39.62%]), sleeve gastrectomy (1,328 [2.29%]), and biliopancreatic diversion (517 [.89%]). The vast majority of index procedures were completed using laparoscopic surgery techniques, except for biliopancreatic diversion, which was primarily done with an open approach. Through May 2009, 78 deaths were reported at any point after the index procedure, for a mortality rate of .13%. The 90-day mortality rate was .11%, and the 30-day mortality rate was .09%. CONCLUSION: This is the first report of data from BOLD. The data have revealed important characteristics of patients undergoing bariatric surgery across the United States in centers participating in the Bariatric Surgery Center of Excellence program. Future analyses of BOLD data are likely to have a major effect on the specialty of bariatric surgery.