Bilateral thalamic infarction is rare and clinically characterized by disturbed vigilance, vertical gaze disorder, amnesic syndrome, convergence difficulty and dysarthria. It can be caused by simultaneous occlusion of either the paramedian thalamic arteries or the tuberothalamic arteries. The clinical manifestations of these two conditions may differ. We report two patients with bilateral thalamic infarction: one due to presumable tuberothalamic arteries occlusion, another due to paramedical thalamic arteries occlusion. We present the clinical and imaging features, and results of neuropsychological tests. SPECTs showed perfusion defect in the cortex. It is suggested that the impairment of attention, speech, cognition and behavior after bilateral thalamic infarcts is related at least in part to the disturbances of the cortex which is functionally connected with the thalamus. Korean Journal of Stroke 2000;2(2): 212~217