OBJECTIVES: To report contemporary outcomes of gastric bypass for obesity and to assess the relationship between provider volume and outcomes. BACKGROUND: Certain Florida-based insurers are denying patients access to bariatric surgery because of alleged high morbidity and mortality. SETTINGS AND PATIENTS: The prospectively collected and mandatory-reported Florida-wide hospital discharge database was analyzed. Restrictive procedures such as adjustable gastric banding and gastroplasty were excluded. RESULTS: The overall complication and in-hospital mortality rates in 19,174 patients who underwent gastric bypass from 1999 to 2003 were 9.3% (8.9-9.7) and 0.28% (0.21-0.36), respectively. Age and male gender were associated with increased duration of hospital stay (P < 0.001), increased in-hospital complications [age: odds ratio (OR) = 1.11, CI: 1.08-1.13; male: OR = 1.53, CI: 0.36-1.72] and increased in-hospital mortality (age: OR = 1.51, CI: 1.32-1.73; male: CI = 2.66, CI: 1.53-4.63), all P < 0.001. The odds of in-hospital complications significantly increased with diminishing surgeon or hospital procedure volume (surgeon: OR = 2.0, CI: 1.3-3.1; P < 0.001, 1-5 procedures relative to >500 procedures; hospital volume: OR = 2.1, CI: 1.2-3.5; P < 0.001, 1-9 procedures relative to >500 procedures). The percent change of in-hospital mortality in later years of the study was lowest, indicating higher mortality rates, for surgeons or hospitals with fewer (< or =100) compared with higher (> or =500) procedures. CONCLUSION: Increased utilization of bariatric surgery in Florida is associated with overall favorable short-term outcomes. Older age and male gender were associated with increased morbidity and mortality. Surgeon and hospital procedure volume have an inverse relationship with in-hospital complications and mortality.