Obesity and type 2 diabetes mellitus have been associated with higher morbidity and mortality. Bariatric surgery results in substantial and sustained weight loss in morbidly obese patients and improves obstructive sleep apnea. Furthermore, bariatric surgery improves diabetes control, hypertension, quality of life, stroke, myocardial infarction and reduces mortality. Interestingly, bariatric surgery induces high rates of short and long-term diabetes remission. While the exact mechanisms behind this are not completely understood, improved insulin action, b-cell function and a complex interplay of hormones in the entero-insular axis appear to play major roles. Insulin action improves proportionally to weight loss and it gets completely normalized especially after bilio-pancreatic diversion. b-Cell function also seems to improve after a variety of bariatric surgeries. Seemingly, baseline b-cell function is able to predict future diabetes remission. This article will review the effectiveness of bariatric procedures on the remission and improvement of diabetes and its implicated mechanisms.Type 2 diabetes mellitus (T2DM) and obesity are major and increasingly common global health problems [1,2]. The relationship involves two main defects, that is, insulin resistance and b-cell dysfunction [3]. Future forecasts point to a gloomy picture with 439 million people being predicted to have diabetes by 2030 [4]. Additionally, the Edmonton obesity staging system proposed by Sharma et al. pointed to increased mortality proportionate to severity of obesity [5]. This calls for the institution of effective therapies to deal with the rising trend of complications arising out of this dual menace of diabetes and obesity.Dietary modification and lifestyle changes form the cornerstone of therapy for both the ailments. Look AHEAD (Action for HEAlth in Diabetes) study demonstrated that intensive lifestyle measures result in significant weight loss and reduced glycated hemoglobin levels.At 1 year, these interventions resulted in higher remission of T2DM than routine lifestyle advices. However, the average weight loss in the intensive lifestyle intervention group decreased from 8.6% in the first year to 4.7% in the fourth year and the rate of patients achieving T2DM remission markedly reduced from 12% in the first year to 7% in the fourth year, indicating that weight loss and glycemic control is difficult to maintain in the long term with lifestyle interventions [6]. With modest weight loss following nutritional therapy, physical exercise and intensive pharmacotherapy, bariatric surgery is increasingly acquiring a prominent role. NIH recommends its use in morbidly obese (BMI ‡ 40 kg/m 2 ) or patients with BMI ‡ 35 kg/m 2 with co-morbidities such as diabetes and hypertension [7]. Other recent recommendations are mentioned in .Bariatric surgeries are of three types. Restrictive procedure -adjustable gastric band (AGB), sleeve gastrectomy (SG); malabsorptive procedure -duodenojejunal bypass (DJB); and mixed procedure -biliopancreatic diversion...