Causes contributing to diabetic nephropathy evolution are many also if the primary is the hyperglycemia. This study treats many parameters (arterial hypertension, albuminuria, etc.) but focuses primarily the importance of intraglomerular pressure, glomerular hypertrophy and anomalies of elements constituting the glomerulus in the pathogenesis of this complex pathology, which diagnostic stage of is fundamental for the institution of a correct and lasting therapeutic approach.