Soon after their discovery microRNA (miRNA) emerged as central natural regulators of gene expression. Although the complex mechanisms of action and impact of miRNA on development, physiology and disease are still elusive, significant progress has been made in deciphering the roles of some miRNA in insulin secretion and action. Here we examine the close relationship existing between miRNA and glucose metabolism as well as their putative role in the pathogenesis of diabetes and their possible utility as biomarkers of this disease.