Abstract: In this study, plasma concentration of atrial natriuretic polypeptide （ANP） in 85 atients with acute cerebrovascular diseases （CVD） was determined by radioimmunoassay. The esults showed that the plasma ANP in these patients increased in 24 to 48 hours and one week fter stroke with no relation to the changes of mentality and EEG. The plasma ANP in patients ith cerebral hemahorrage, 24 to 48 hours after CVD, was significantly increased in the total ase. There was no significant change 2 weeks after the onset of CVD. It was suggested that the ncrease of plasma ANP in 24 to 48 hours after CVD may be the reaction to the stress and that his condition in patients with cerebral hemahorrate is usually serious.