Electron microscopy and NTA verified a typical shape of exosomes with an average diameter of 100.7 nm, and western blot identified the presence of CD9, Alix, and TSG101 on exosomes. let-7c-5p was significantly upregulated in urinary exosomes of DN patients compared with controls (p < 0.05), while miR-29c-5p and miR-15b-5p were significantly downregulated compared with healthy controls (p < 0.05). let-7c-5p is correlated with both estimated glomerular filtration rate (r = -0.723, p < 0.001) and progression of DN. All three miRNAs, let-7c-5p, miR29c-5p, and miR-15b-5p, could predict DN with AUC of 0.818, 0.774, and 0.818, respectively.