Several -blockers increase VLDL-TG and decrease HDL-cholesterol concentrations. The underlying mechanism ist not yet clear. Some studies have suggested that the effect is less pronounced during treatment with selective -blockers. The effects of 2 such drugs, metoprolol 200 mg/day and atenolol 50 mg/day, have been compared in 50 hypertensive patients (WHO Stage I–II), mean age 47 years. Serum lipoproteins were determined in 20 patients before treatment and after treatment with either drug for 3 months. Both drugs were equally effective in reducing blood pressure. After atenolol the initial VLDL-cholesterol concentration of 1.04 mmol/l had not changed, but it rose to 1.29 mmol/l after metoprolol (p<0.05). the="" hdl-cholesterol="" concentration="" 1.42="" mmol/l="" did="" not="" fall="" during="" atenolol="" treatment,="" but="" during="" metoprolol="" there="" was="" a="" small="" reduction="" to="" 1.31="" mmol/l="">p<0.05). hyperlipoproteinaemia="" is="" common="" in="" hypertensive="" patients,="" 40%="" of="" the="" present="" group="" had="" hypertriglyceridaemia="" and="" 25%="" had="" hypercholesterolaemia.="" thus,="" atenolol="" 50="" mg="" was="" found="" not="" to="" affect="" lipoproteins,="" whereas="" metoprolol="" 200="" mg="" increased="" the="" vldl="" concentration="" in="" 75%="" of="" the="">