The variability of chest pain is described in 389 patients with acute myocardial infarction. Whereas 17% were free from severe pain after arrival in hospital, 11% required more than 10 analgesic injections. In 27% of the series analgesics were given more than 24 h after arrival in hospital. Predictors for the severity of chest pain were the rate-pressure product and degree of chest pain soon after arrival in hospital as well as electrocardiographic signs of myocardial infarction at entry. Patients with more severe chest pain had a higher 2-year mortality rate and a higher incidence of ventricular fibrillation and congestive heart failure during hospitalization.