Abstract: The epidemiological relationship between nephrolithiasis and hypertension is wellknown. Patients with hypertension are at increased risk for nephrolithiasis and those with nephrolithiasis are at risk for hypertension. An anomaly in RBC Oxalate transport and reduced activities of adenosine triphosphatases has been reported in patients with hypertension when compare to control subjects. This study presents an abnormal increase in transmembrane flux of oxalate in RBC of hypertensive subjects and it might be due to membrane degradation caused by oxalate-induced free radicals depleting erythrocyte thiol contents and impaired adenosine triphosphatases activity resulting in tissue injury and defective membrane transport. Thus relative risk of hypertension was significantly associated with increased oxalate flux rate and impaired adenosine triphosphatases activity in stone formers. This association is important when treating patients with nephrolithiasis since those with hypertension may require unique dietary and medical therapy.