Diabetic nephropathy is characterized not only by glomerular disease but also tubulointerstitial injury. The tubular changes associated with diabetic nephropathy, include basement membrane thickening, tubular hypertrophy, epithelial-mesenchymal transition, glycogen accumulation and interstitial inflammation. Although glomerular changes has received significantly more attention from researchers and clinicians than tubulointerstitial changes in diabetes, tubular injury is known to associate better with renal function than glomerular injury. In fact, tubular proteinuria may precede microalbuminuria with type 1 diabetes, suggesting that tubular damage may be induced earlier than glomerular injury in the course of diabetic nephropathy.