This review article deals with the role of beta blockade in the limitation of infarct development. A large number of studies have reported that early administration of beta blockers limits infarct size in animals. In a few, however, these results were not reconfirmed. In man, several large randomized trials have shown that early administration of beta blockade limits infarct development judged from serum enzyme activity and ECG recordings. Delay time between the onset of symptoms and start of treatment is of major importance. It appears as though patients with a higher initial rate pressure product respond most favourably. Although these results are encouraging, the role of infarct limitation in relation to effects on early mortality, chest pain and arrhythmias have not been clearly defined.