Introduction: Obesity has experienced worldwide increase and surgery has become the treatment that has achieved the best results. Several techniques have been described; the most popular are vertical gastrectomy (GV) and the Roux-en-Y gastric bypass (RYGB). However, mini-gastric bypass/one anastomosis gastric bypass (MGB/OAGB) has gained popularity due to its simplicity and good results. Objective: To comparatively evaluate the results of MGB/OAGB with those of RYGB with 1-year follow-up. Methods: The paper presents a comparative case and control study of 100 patients that underwent MGB/OAGB surgery and another 100 with RYGB surgery, operated between 2008 and 2016. Patients were not submitted to revision surgery and had the following pre-operative variables: age 40.46 +/- 12.4 vs. 39.43 +/- 10.33 years; sex 64 and 54 women, 36 and 46 men; BMI 44.8 +/- 12.06 and 45.29 +/- 8.82 kg/m(2); 50 and 54 cases with comorbidities, respectively, these being non-significant differences. Results: The surgical time was 69.01 +/- 4.62 (OAGB) vs. 88.98 +/- 3.44 min; the time of hospitalization was 2 days, reaching a BMI of 27.7 +/- 7.85 and 29 +/- 4.52 kg/m(2), with an excess weight loss 1 year after surgery of 89.4 vs. 85.9%, respectively. The morbidity rates are 9% for OAGB and 11% for the RYGB. There was a comorbidity resolution of 84.4 and 83.7% respectively, without mortality. Conclusions: The results show the benefits of both techniques, OAGB being the easiest to perform and with less surgical time.