Endothelial damage is an important component of atherosclerosis. Increased levels of sTM in plasma have been reported in atherosclerosis, DM, proliferative diabetic retinopathy and systemic lupus erythematosis. Plasma sTM concentrations may reflect the endothelial expression of TM which posses several properties to protect arterial walls and reduce thrombotic tendency. This study was conducted to find out the plasma levels of sTM in patients with acute myocardial infarction (AMI) or acute ischemic stroke (AIS). The study was carried out on two groups one group include 20 patients with previous ischemic stroke (10 diabetic &10 non-diabetic)& another group include 20 patients with coronary atherosclerosis (10 diabetic &10 non-diabetic). A control group includes 10 healthy non-smokers subjects of compatible age & sex. Acute myocardial infarction (AMI) and acute ischemic stroke (AIS) are associated with decreased plasma sTM reflecting decreased expression of endothelial TM thus disturbing the balance between procoagulant and anticoagulant factors towards a procoagulant state. In patients with AIS diabetics have lower plasma sTM than non-diabetics.