This paper shows the eventual benefits of treatment with beta-blockers in post-myocardial infarction. An overview of main clinical trials that have been conducted to test this therapeutic in acute coronary syndrome. In patients presenting with acute myocardial infarction, the early use of intravenous beta-blockers had shown a modest and non significant reduction in mortality. Substantial reductions in mortality and reinfarction have been demonstrated when beta-blockers have been used soon after an acute myocardial infarction and continued long-term. However, these benefits were observed in randomised clinical trials conducted in the 1970s and 1980s, prior to the widespread use of reperfusion therapies and antiplatelet agents. It appears obvious that the long-term use of beta-blockers may be questionable after any acute coronary syndrome especially if complete reperfusion has been achieved and left ventricular function is preserved.