HYPOTHESIS: Gastric bypass corrects comorbidities and quality of life similarly in superobese (SO) and morbidly obese (MO) patients despite higher residual weight in SO patients. DESIGN: Prospective cohort study comparing results of primary laparoscopic gastric bypass in MO and SO patients. SETTING: University hospital and community hospital with common bariatric programs. PATIENTS: A total of 492 MO and 133 SO patients treated consecutively between January 1, 1999, and June 30, 2006. INTERVENTION: Primary laparoscopic Roux-en-Y gastric bypass. MAIN OUTCOME MEASURES: Operative morbidity, weight loss, residual body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared), evolution of comorbidities, quality of life, and Bariatric Analysis and Reporting Outcome System score. RESULTS: Surgery was longer in SO patients, but operative morbidity was similar. The MO patients lost a maximum of 15 BMI units and maintained an average loss of 13 BMI units after 6 years, compared with 21 and 17 in SO patients, which corresponds to a 30.1% and 30.7% total body weight loss, respectively. After 6 years, the BMI was less than 35 in more than 90% of MO patients but in less than 50% of SO patients. Despite these differences, improvements in quality of life and comorbidities were impressive and similar in both groups. CONCLUSION: Although many SO patients remain in the severely obese or MO category, equivalent improvements in quality of life and obesity-related comorbidities indicate that weight loss is not all that matters after bariatric surgery.