European and North-American guidelines for the diagnosis and therapy of arterial hypertension refer to hypertensive crisis as an acute and critical increase of blood pressure>180/120 mmHg. Presence of acute hypertensive target organ damage, such as stroke, myocardial infarction or heart failure, in this situation defines a “hypertensive emergency”. In these patients, immediate lowering of blood pressure (about 25% within one to two hours) in an intensive care setting is mandatory to prevent further progression of target organ damage. In contrast to hypertensive emergencies, hypertensive urgencies are characterized by an acute and critical increase in blood pressure without signs or symptoms of acute hypertensive target organ damage. In these patients, blood pressure should be lowered within 24 to 48 hours in order to avoid hypertensive target organ damage. In general, hospitalization is not required, and oral antihypertensive therapy usually is sufficient. However, further and continuing outpatient care has to be ensured.