Background. The mechanism of stroke in beta-thalassemia was reported previously as cardioembolic and hypercoagulable state. However, there is no report of watershed infarct in beta-thalassemia anemia. Method. We present an adult β-thalassemia major patient with manifest asymptomatic chronic left carotid occlusion who suffered watershed infarct. Result. In the presence of asymptomatic chronic left internal carotid occlusion, we assumed that severe anemia (hemoglobin = 3) at admission leads to watershed infarct. Conclusion. Watershed infarct seems to be the cause of stroke in cases of β-thalassemia major with severe anemia. Blood transfusion can be applied in the setting of acute brain ischemia in such high risk patients.