Bariatric surgery becomes more and more important in the management of the obese patient with type 2 diabetes, especially in case of failure of medical approaches. Metabolic improvement results not only from weight loss and the subsequent reduction in insulin resistance, but also from modifications of digestive hormones (especially incretins) that contribute to promote insulin secretion. This new paradigm, moving from bariatric surgery to metabolic surgery, opens new perspectives. The present article briefly describes innovative surgical techniques focusing on endocrine and metabolic improvement rather than on weight loss, the preliminary results of metabolic surgery in patients with type 2 diabetes and a body mass index <35 kg/m2 and, finally, some data regarding the surgical management of obese patients with type I diabetes not well treated with classical medical means.