In 47 patients admitted to the coronary care unit (CCU) at Sahlgren's Hospital because of acute myocardial infarction (MI), we evaluated the intensity of pain before admission and during the first 24 hours in the CCU and the delay time between the onset of symptoms and the decision to go to the hospital. Pain was assessed according to a modified visual analogue scale graded from 0 to 10, where 0 meant no pain and 10 meant the most severe pain. Patients generally scored their maximal pain before admission higher than their pain in the CCU. The maximal pain before admission did not seem to differ between patients with larger and smaller infarcts, estimated from maximal serum enzyme activity, whereas patients with larger infarcts tended to have more intensive pain in the hospital despite consuming more analgesics during the first 3 hours and the first 24 hours in the CCU. The time between onset of symptoms and decision to go to the hospital was not influenced by the intensity of pain before admission, but patients with larger infarcts made their decision much faster than those with smaller infarcts. In conclusion, infarct size, a major determinant of the initial prognosis, appeared to influence the initial pain course in the CCU and to markedly affect the delay time between onset of symptoms and the decision to seek medical care.