Context Few studies have evaluated the results of different types of bariatric surgery using the Medical Outcome Study 36 - Health Survey Short-Form (SF-36) quality of life questionnaire, the Bariatric and Reporting Outcome System (BAROS) and the reviewed Moorehead-Ardelt Quality of Life II Questionnaire (M-A QoLQ II) that is part of BAROS. The Roux-en-Y gastric bypass (RYGB) is the most common morbid obesity surgery worldwide. However, there is evidence indicating that a biliopancreatic diversion with duodenal switch (DS) is more effective than RYGB in weight loss terms. Objectives To evaluate the impact of different types of bariatric surgery on quality of life, comorbidities and weight loss. Methods Two groups of patients who underwent bariatric surgery conventional Banded Roux-en-Y gastric bypass (BRYGB) or DS were evaluated through monitoring at 12 to 36 months after surgery, as well as a control group of obese patients who had not undergone surgery. The tools used for this were SF-36, BAROS and M-A QoLQ II. The DS group consisted of 17 patients and the BRYGB group consisted of 20. The control group comprised 20 independent, morbidly obese individuals. Results The mean age of the patients in the groups was 45.18 in the DS group, 49.75 in the BRYGB group and 44.25 in the control group, with no significant difference. There was no difference in the ratio of men to women in the groups. The patients that had surgery showed a significant improvement in all domains of quality of life vs the control group. Comparing the two groups that underwent surgery, the DS group achieved better quality of life results in terms of "general state of health" and "pain", according to responses to the SF-36 tool, and in terms of "sexual interest", according to responses to the M-A QoLQ II tool. There was no significant difference among the three groups regarding the ratio of occurrence of comorbidities. In the groups that had surgery, the resolution of comorbidities was similar. The final classification according to the BAROS Protocol was excellent for the DS group and very good for the BRYGB group, with a statistical difference in favor of the DS group (P = 0.044*). There was no difference in the percentages of excess weight loss between the DS group (82.1%) and the BRYGB group (89.4%) (P = 0.376). Conclusions A comparison of the performance of the groups, which were monitored from 12 to 36 months after surgery, showed that the two types of surgery are effective to improve quality of life, comorbidities and weight loss. The DS surgery produced better results in the quality of life evaluations regarding 2 of 8 domains according to the SF-36, and "sexual interest" according to the M-A QoLQ II. In the groups that had surgery, the patients showed high rates of comorbidity resolution. Weight loss was similar for the two surgical groups.