The duration of patient delay from the time of onset of symptoms of acute myocardial infarction (AMI) to hospital presentation, and the relation of delay time and various patient characteristics to receipt of thrombolytic therapy were examined as part of a community-based study of patients hospitalized with AMI in the Worcester, Massachusetts, metropolitan area. In all, 800 patients with validated AMI hospitalized at 16 hospitals in the Worcester metropolitan area in 1986 and 1988 constituted the study sample. Patients delayed on average 4 hours between noting symptoms suggestive of AMI and presenting to area-wide emergency departments with no significant change observed between 1986 and 1988. The shorter the time interval of delay, the greater the likelihood of receiving thrombolytic therapy; patients arriving at the emergency department within 1 hour of the onset of acute symptoms were approximately 2.5 and 6.5 times more likely to receive thrombolytic agents than were those presenting to the hospital between 4 and 6, and greater than 6 hours, respectively, after the onset of symptoms. Results of a multivariate analysis showed increasing length of delay, older age, history of hypertension or AMI and non-Q-wave AMI to be significantly associated with failure to receive thrombolytic therapy.