The molecular background of mitochondrial dysfunction in adipose tissue of morbidly obese individuals and bariatric surgery-induced changes in adipose mitochondrial function remain incompletely understood. To evaluate the mechanisms behind the surgery-induced changes and differences between morbidly obese subjects and nonobese controls, we performed a LC-MS/MS proteomics analysis of abdominal subcutaneous (SAT) and visceral adipose tissue samples (VAT) collected from the bariatric surgery, SAT samples collected 6 months after surgery, and control SAT and VAT samples collected from baseline.