Abstract: The number of diabetics in China, especially those of type 2 diabetes mellitus, has increased rapidly in decades. However, the pathogenesis of diabetes mellitus is still not clear, with still no effective method to treat the disease. Studies found that exosomes play an important role of carrying a variety of proteins, nucleic acids and lipids and participating in cell-cell communication, with some therapeutic and diagnostic function. This review briefly summarizes the roles of exosomes in diabetes mellitus so as to provide references for their clinical application.