The pre-hospital electrocardiogram (PH-ECG) has been proposed as a means for rapidly identifying patients with acute myocardial infarction (AMI) who might be eligible for reperfusion therapy. In order to ascertain characteristics and outcomes of AMI patients having PH-ECG's, data from the ongoing NRMI-2 were analyzed. Pre-hospital ECG's were obtained in 2,011 (6.3%) of 31,939 NRMI-2 patients who presented to the hospital within 12 hours of an AMI from 6/94 to 7/95. Transfer or self-transport patients were excluded from this study. Median time from AMI symptoms onset until hospital arrival was longer among those treated with PH-ECG (2.8 hrs vs 1.7 hrs, p < 0.001). However, once in the hospital, the PH-ECG treated group conferred a shorter median time to the initiation of either thrombolysis (31 min vs 40 min, p < 0.001) or primary angioplasty (87 min vs 117 min, p < 0.001). The PH-ECG group was more likely to receive thrombolytic therapy (45% vs 38%, p < 0.001) and undergo primary angioplasty (18% vs 10%, p < 0.001). Also, the PH-ECG group was more likely to obtain in-hospital cardiac catheterization (54% vs 39%, p < 0.001), angioplasty (21% vs 15%, p < 0.001) or bypass surgery (10% vs 6%, p < 0.001). Hospital mortality was 7.9% in the PH-ECG group and 12.2% in those without PH-ECG (p <0.001). After adjusting for baseline differences utilizing multi-variate analysis, this mortality difference remained statistically significant (p = 0.02). In NRMI-2, the pre-hospital ECG in diagnosing AMI leads to the wider, faster inhospital utilization of reperfusion strategies, as well as the greater use of invasive procedures. These factors may help explain the mortality advantage seen in the PH-ECG treated group.