The effect of cessation of chronic beta-adrenoceptorblockade on heart rate, blood pressure, blood lipids and selected haemostatic factors have been measured in 22 patients recovering from myocardial infarction. Clinical examination and blood tests were performed before and 12 weeks after withdrawal of beta-adrenoceptor-blockade, which had lasted for an average of 3 y. No effect was found on blood pressure. There was a significant increase in heart rate of 12%. Total cholesterol declined by 9%, high density lipoprotein (HDL-cholesterol) increased by 12%, and triglycerides decreased by 6%. The triglyceride dependent factors, plasminogen activator inhibitor (PAI-1) and factor VII-phospholipid complex, were not affected.