Several epidemiological and clinical studies, carried over the past 30 years, have unequivocally shown that high blood pressure is an important risk factor for development of myocardial infarction. The risk level, which has been documented for an increase both in systolic and diastolic blood pressure values, further increases when hypertension is accompanied with other conditions (e.g. hyperlipidemia, diabetes, cigarette smoking) well-known to adversely affect the cardiovascular system. Antihypertensive treatment significantly decreases, although without normalizing, the incidence of coronary events in the hypertensive patient, the reasons for this only partial cardioprotection being so far largely unknown. More complex and less documented are the relationships between hypertension and myocardial reinfarction. Although there is no doubt that high blood pressure levels increase the incidence of reinfarction, it should be emphasized that no study so far has been undertaken to clarify the effectiveness of antihypertensive treatment in reducing the risk of myocardial infarction and in improving the prognosis of the disease.