beta-receptor antagonist as antihypertensive agent has adverse effect such as vasoconstriction, bronchoconstriction and aggravation of atherosclerosis. So beta-receptor antagonist with alpha-receptor blocking property has been studied for avoidance of adverse effects of beta-receptor antagonist. Nipradilol, a new beta-receptor antagonist with alpha-receptor blocking property was administrated in 30 essential hypertensive patients for 10 week in order to evaluate the antihypertensive effects and adverse effects. The results were as follows: 1) Nipradilol was effective in 20 patients(67%) on systolic blood pressure 22 patients (73%) on diastolic blood pressure at the end of 10 weeks treatment. 2)Before medication, mean systolic and diastolic blood pressure in sitting position were 160+/-14mmHg and 102+/-18mmHg,and after 10 weeks of medication, mean systolic and diastolic blood pressure were significantly declined to 143+/-22mmHg and 89+/-12mmHg(p<0.001). 3) There was no significant change in pulse rate, from 78+/-12 beats per minute the beginning of the treatment to 75+/-11 beats per minute after 10 week of treatment. 4) There was no significant changes in sodium, potassium, GOT, GPT, bilirubin, alkalin ephosphatase, BUN, creatinine, LDH, CPK and lipid. 5) The adverse effects of nipradilol were bradycardia(7%), dyspnea(3%), chest discomfort(3%) and headache(3%). In summary, nipradilol seemed to be effective antihyertensive drug in treating mild to moderate hypertension.