Nephrologists deal with a host of pathologic conditions involving renal and systemic endothelium. Both in native and transplanted kidneys, often the insult to the renal endothelium initiates the pathogenic process ultimately leading to the loss of organ function. Also, systemic atherosclerosis is accelerated in patients with renal dysfunction. In this review we would like to cover the possible role of CECs and their counterparts--circulating EPCs in the pathogenesis of endothelial dysfunction associated with chronic renal failure, ANCA-associated vasculitis, and progression of chronic renal disease.