The betablockers are the most important drugs in the secondary prevention after myocardial infarction. Several studies have shown that, in patients without a contraindication to these drugs, betablockers reduce the mortality and recurrence of infarction by about 25%. The best results observed in the subgroup of patients with criteria of severity (previous myocardial infarction or cardiac failure, left ventricular dysfunction, arrhythmias, residual ischaemia, occluded artery or triple vessel disease) has been shown in the APSI and BHAT studies where the reduction in mortality was almost 50% in the subgroup of patients with cardiac failure. The duration of treatment and the role of betablockers with respect to ACE inhibitors are not as clearcut in 1996.