Abstract: This article mainly reportes the procedure by which the plasma ANP levels in elderly patients with cardiovascular and cerebral diseases, using a sensitive RIA devloped in our laboratory.The plasma ANP levels in patients with advanced stage PHD were significantly lower than those with early stage PHD （P＜0.05）. The ANP values of plasma in 14 with LVH are significantly higher than those in 16 with normal size left ventricle （p＜0.01）. The ANP concentritions of plasma of patients with cerebral stroke in the presene of hypertension are 861.1 ±108.4 in pafients with higher BP and 536.8±50.2 in pafients with normal BP.In summary, determination of plasma ANP levels in the eldery patients plays an important role in understanding the mechanism and severity of cardiovascular and cerebral diseases.