In 334 consecutive admissions for acute stroke, the blood pressure was elevated in 84% on the day of admission. The blood pressure decreased spontaneously an average of 20 mm Hg systolic and 10 mm Hg diastolic in the ten days following the acute event without specific antihypertensive therapy and was elevated in only one third of the cases on the tenth hospital day. The early elevation in blood pressure is likely a physiological response to brain ischemia, and blood pressure falls as recovery of brain function occurs.