Nineteen patients with mild essential hypertension received 20 mg of arotinolol daily for 12 weeks. The patients' systolic and diastolic blood pressures and pulse rate decreased significantly after arotinolol. The ratio of apolipoprotein B to apolipoprotein A-I decreased significantly after treatment. No significant changes were observed in serum and lipoprotein lipid levels, apolipoprotein levels, or in the ratio of low-density lipoprotein cholesterol to high-density lipoprotein cholesterol. The results indicate that arotinolol is an effective antihypertensive agent with favorable effect on apolipoproteins.