INTRODUCTION: Lipoprotein(a) [Lp(a)] is a genetically determined risk factor of coronary heart disease and its complications. Meanwhile data about the role of Lp(a) in development of ischemic stroke are controversial. AIM: To investigate the association of Lp(a) with atherothrombotic ischemic stroke and stenotic (≥50%) atherosclerosis of carotid arteries. MATERIAL AND METHODS: The study included 490 patients (mean age 60 years, 53% male). The first group comprised 157 patients with ischemic stroke, the second group 68 patients with isolated stenotic atherosclerosis of carotid arteries, but without significant lesion of coronary and low limbs arteries. The control group included 265 patients without stroke, myocardial infarction, stenotic atherosclerosis of coronary, carotid and low limbs arteries according to instrumental examinations. The levels of Lp(a) and lipids were measured in blood serum of all patients. RESULTS: Lp(a) concentration was significantly higher in patients of the first and second groups in comparison with the control group (median [interquartile range]): 24 [9; 48], 20 [8; 55] vs 13 [5; 27] mg/dl, respectively (p<0,05 in both cases). Hyperlipoproteinemia(a) (Lp(a) ≥30 mg/dl) was more frequent in the group with stroke, stenotic atherosclerosis of carotid arteries, than in the control group: 43%, 40% vs 22% (p<0.01 in all cases). In patients with hyperlipoproteinemia(a), odds ratio (OR) for ischemic stroke was 2.7 (95% confidence interval (CI) 1.7-4.1), and OR for stenotic atherosclerosis of carotid arteries was 2.3 (95% CI 1.3-4.0) compared to the patients with Lp(a) level <30 mg/dl (p<0.01 in both cases). In logistic regression analysis adjusted for age, sex, hypertension, type 2 diabetes, smoking and Lp(a) concentration, the hyperlipoproteinemia(a) was associated with ischemic stroke and isolated stenotic carotid atherosclerosis. In the group with severe carotid atherosclerosis, 16 patients (24%) had ischemic stroke. Lp(a) concentration in these patients was higher 36 [20; 59] mg/dl, than in the patients with isolated carotid atherosclerosis without stroke 15 [7; 54] mg/dl (p=0.04). Other risk factors of atherosclerosis did not differ in patients with or without ischemic stroke. CONCLUSION: The study shows the association of elevated level of Lp(a) with ischemic stroke and isolated stenotic atherosclerosis of carotid arteries. In the presence of isolated stenotic carotid atherosclerosis, the median of Lp(a) concentration was significantly higher in patients with ischemic stroke than in patients without stroke.