Excellent results have been reported with mini-gastric bypass. We adopted and modified the one-anastomosis gastric bypass (OAGB) concept. Herein is our approach, results, and long-term follow-up (FU). Initial 1200 patients submitted to laparoscopic OAGB between 2002 and 2008 were analyzed after a 6-12-year FU. Mean age was 43 years (12-74) and body mass index (BMI) 46 kg/m(2) (33-86). There were 697 (58 %) without previous or simultaneous abdominal operations, 273 (23 %) with previous, 203 (17 %) with simultaneous, and 27 (2 %) performed as revisions. Mean operating time (min) was as follows: (a) primary procedure, 86 (45-180); (b) with other operations, 112 (95-230); and (c) revisions, 180 (130-240). Intraoperative complications led to 4 (0.3 %) conversions. Complications prompted operations in 16 (1.3 %) and were solved conservatively in 12 (1 %). Long-term complications occurred in 12 (1 %). There were 2 (0.16 %) deaths. Thirty-day and late readmission rates were 0.8 and 1 %. Cumulative FU was 87 and 70 % at 6 and 12 years. The highest mean percent excess weight loss was 88 % (at 2 years), then 77 and 70 %, 6 and 12 years postoperatively. Mean BMI (kg/m(2)) decreased from 46 to 26.6 and was 28.5 and 29.9 at those time frames. Remission or improvement of comorbidities was achieved in most patients. The quality of life index was satisfactory in all parameters from 6 months onwards. Laparoscopic OAGB is safe and effective. It reduces difficulty, operating time, and early and late complications of Roux-en-Y gastric bypass. Long-term weight loss, resolution of comorbidities, and degree of satisfaction are similar to results obtained with more aggressive and complex techniques. It is currently a robust and powerful alternative in bariatric surgery.