Hypertension complicates most cases of chronic kidney disease. While the prevalence and severity of hypertension increase as glomerular filtration rate falls, hypertension is often observed in patients with structural kidney disease while renal function is normal, in particular those with polycystic kidney disease or proteinuric glomerular diseases. On the other hand, even severe reductions in renal function may not result in hypertension, especially if there is effective control of extracellular fluid volume. Recent clinical and experimental data indicate that proteinuria may mediate sodium retention and hypertension via plasmin-mediated activation of the epithelial sodium channel. Current evidence supports the notion that chronic kidney disease is a cause of chronic hypertension, even in the absence of detectable changes in glomerular filtration rate.