BACKGROUND: Extent of delay in seeking medical care in persons with acute myocardial infarction (AMI) is receiving increasing attention, given the time-dependent benefits associated with early administration of coronary reperfusion therapy. OBJECTIVE: To examine recent data, and temporal trends therein, about duration of prehospital delay in a large (N = 364,131) cross-sectional sample of patients included in the second National Registry of Myocardial Infarction. METHODS: The medical records of patients hospitalized with AMI in 1624 US hospitals from June 1, 1994, to October 31, 1997, were reviewed for information about duration of prehospital delay. RESULTS: There was evidence of a slight decline in average delay times in patients hospitalized in 1997 (5.5 hours) compared with those hospitalized in 1994 (5.7 hours). Median delay times (2.1 hours) did not change. Approximately 20% of patients presented to the hospital within 1 hour of acute symptom onset, and slightly more than two thirds presented within 4 hours. Delay times were more prolonged for older patients, women, nonwhite patients, and patients with a history of diabetes or hypertension vs respective comparison groups. Patients in cardiogenic shock exhibited shorter delay times than less severely ill patients. Patients with previous AMI or who had undergone previous coronary angioplasty presented to the hospital with shorter delay times, as did individuals hospitalized in the Mountain and Pacific regions. CONCLUSIONS: These results provide insights into recent delay times and into groups at risk for prolonged delay.