In this review article the results of randomised studies of intravenous administration of beta blockers in patients with myocardial infarction (MI) are presented. Intravenous beta blockade followed by oral, within 12 hours (preferably 6) of the onset of chest pain results in: marked reduction in chest pain, limitation of infarct size, diminished likelihood of threatened infarction progressing to overt infarction, reduction in the number of life threatening ventricular arrhythmias and reduction in the incidence of cardiac arrest and reinfarction. A pooled analysis showed that in the 14 reviewed randomized trials the overall reduction of mortality was 13.0% in the beta-blocker patients compared to control patients. Such an intervention, provided contraindications to beta blockade are respected, is safe and well tolerated. Probably, about 50.0% of patients are eligible for such treatment.