Diabetes mellitus is a very common metabolic disorder affecting more than 400 million people worldwide. Currently available treatments permit to manage the disease but, in the long term, many patients develop severe micro- and macrovascular complications that decrease life quality and expectancy. Better therapeutic tools to prevent and treat diabetes are therefore urgently needed. Areas covered: MicroRNAs are key regulators of gene expression and central players in a variety of physiological and pathological processes. This review summarizes the role of microRNAs in insulin-secreting cells and in insulin target tissues as well as their involvement in the development of diabetes and its long term complications. Expert opinion: Because of their physicochemical properties and their capacity to regulate a wide range of physiopathological events, microRNAs are attractive therapeutic targets. There is accumulating evidence that approaches permitting to correct the level of specific microRNAs can successfully prevent or treat diabetes and its complications. Pharmacological tools that efficiently modulate the level of microRNAs are already available. However, before these tools can be allowed to integrate the arsenal for the treatment of diabetic patients, new innovative strategies will be needed to achieve selective delivery of these pharmacological principles to the appropriate target cells.