Fifty patients with occlusive cerebrovascular disease (ischemic thrombotic cerebrovascular disease--ITCBVC) were studied for clinical features, angiographic findings, serum lipids, platelet functions and fibrinolytic activity. Angiograms were abnormal in 24 of 36 cases. Two-thirds of these had an abnormality of the internal carotid artery in the neck; one-third had occlusion of the middle and/or anterior cerebral arteries. A statistically significant rise of serum triglycerides, pre-beta lipoproteins, platelet adhesiveness and aggregation, and a decrease in fibrinolytic activity were noticed in these patients as compared to age and sex matched controls. The correlation coefficient did not show any intercorrelation between the platelet adhesiveness and raised lipid fractions. These factors could be responsible for the atheroma resulting in large vessel occlusion.