The recent increase in the prevalence of obesity seems to be responsible for the increase in T2 Diabetes Mellitus (T2DM). At present around 50 % of T2DM patients are obese and this percentage appears set to increase in the near future. Successful management of T2DM in obese patients is a complicated task, as many parameters such as blood pressure, LDL-cholesterol levels have to be adequately controlled along with HbA1c levels. There is a substantial amount of evidence showing that bariatric surgery achieves long term remission of diabetes in the majority of obese patients and improves significantly comorbidities associated with DM such as dyslipidemia, hypertension, and obstructive sleep apnea. It seems that early surgical intervention before irreversible b-cell damage has occurred, increases the chances of long term T2DM resolution. However, at present a very small percentage (< 2%) of obese patients with T2DM is treated surgically. The present review focuses on the efficacy and safety of the main bariatric procedures. It also emphasizes the mechanism with which bariatric surgery exerts its therapeutic effect and on the long term results on T2DM remission.