An analysis has been made of the clinical manifestations in 18 cases of hypertensive thalamic hemorrhage diagnosed by computed tomography (CT). CT scans permitted accurate determination of the site, size, and extension of the hemorrhages. A sensorimotor hemiplegia or hemiparesis was present in all cases. Diagnostic clinical features included limitation of vertical gaze, downward deviation of the eyes, and small unreactive or sluggish pupils. All hemorrhages larger than 3.3 cm in diameter were fatal.