Factors affecting hospitalization delay and sudden death were studied in 98 patients with acute myocardial infarction in an industrial population. History of heart disease and misinterpretation of symptoms as recurrence of angina delayed arrival to hospital. In 19 of 22 patients dying suddenly, there was a history of a previous myocardial infarction or angina. The same factors that delay hospital arrival are associated with sudden death. The use of a fixed satellite industrial coronary care unit shortened arrival time when symptoms began at work, but had an adverse effect when symptoms occurred off work. The unit did not reduce sudden death mortality.