Diabetes mellitus is a group of metabolic disorders of carbohydrate metabolism in which glucose is underutilized, producing hyperglycemia. The latter complications of diabetes mellitus include microvascular complications the major microvascular complications, retinopathy and nephropathy, are the more important causes of blindness and end-stage renal disease in Europe. Different risk factors such as diabetes duration, blood pressure and lipid control have consistently been shown to correlate with both microvascular complications for diabetes. Despite the efforts of studies to correlate the two major diabetes mellitus microvascular complications, retinopathy and nephropathy, the relationship has not so far been clearly described. However, the currently literature data suggest that the presence of a pre-existing microvascular complication (retinopathy or nephropathy) may contribute to the development of another, especially in DM1 patients. More prospective studies are needed if we are to know the exact mechanism of how these diabetic microvascular diseases correlate, and if we are to develop a scoring system for predicting the development of those complications that will allow us to identify the patients at risk, with its consequent positive impact on patients' quality of life. The aim of the present study is to review the literature on the diagnosis, epidemiology, pathology, and risk factors in diabetic nephropathy and retinopathy, and then a revision of the possible relation between renal and retinal diabetic microangiopathy.