In order to determine the prevalence of arterial hypertension and clinical presentation of the hypertensive crisis, as well as the need and efficacy of treatment, 3626 patients who were seen at an Emergency care Unit during a period of 37 randomly chosen days in a total time period of three months, have been studied. Two hundred and fifty one patients presented arterial hypertension, defined as a systolic arterial pressure above 160 mmHg and/or diastolic above 95 mmHG, which represents 6,92% of medical emergencies and 1.79% of total emergencies. Only 104 patients (2.86%) seeked help for some pathology related to hypertension, of whom 49 (19.5% of hypertense patients) presented as a hypertensive emergency, being the acute lung edema and unstable angina the most frequently encountered emergencies. Nifedipine was the most frequently used drug in both groups and managed to control pressure levels in almost 90% of patients with a hypertensive emergency in a mean time of less than one hour.