Blood pressure changes in the acute phase of stroke are common. High blood pressure is often found on admission as a psychological reaction to stress--a white coat effect. Both high and low blood pressure relate to poor outcome after stroke. At the moment there is no evidence for pharmacological modification of blood pressure in the acute phase of stroke based on randomized controlled trials. Antihypertensive treatment as a secondary preventive measure should at least be started if blood pressure is stable and higher than 140/90 mmHg a few days after stroke onset.