The EcoR1 polymorphism of the apolipoprotein B gene (APOB) is thought to be associated with atherothrombotic type of ischemic stroke (ATTIS) with the APOB*R1/R2 genotype as a marker of increased risk for ATTIS. We estimated odds ratio for this genotype as 2.17 in ethnic Russians and 3.39 in ethnic Tartars. The association between the EcoR1 APOB gene polymorphism and ATTIS confirmed the results of previous studies on relation of the APOB gene to vascular pathology caused by elevated lipid level and atherogenesis.