Patients with ST-elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI) are increasingly being treated with percutaneous coronary intervention (PCI) and we sought to determine risk of adverse outcomes by type of MI. Patients enrolled in the National Heart, Lung, and Blood Institute Dynamic Registry from 1999 to 2004 who presented with an acute MI as an indication for PCI were studied. Baseline data and in-hospital and 1-year outcomes were compared based on ST-segment elevation (STEMI, n = 903; NSTEMI, n = 583) at presentation. Patients with STEMI were younger, had fewer co-morbidities, and had less extensive coronary artery disease than did patients with NSTEMI. Angiographic success and periprocedural complications were similar by MI type. In-hospital coronary artery bypass grafting, stroke, bleeding and recurrent MI were similar but mortality was higher in patients with STEMI (4.0% vs 1.4%, p = 0.004). Cardiogenic shock was associated with the greatest risk of in-hospital death (odds ratio 26.7, 95% confidence interval 11.4 to 62.3, p = 0.0001), but STEMI was also independently predictive of mortality. At 1 year, there was no influence of MI type on outcome. Age, cardiogenic shock, renal disease, peripheral vascular disease, and cancer were predictive of death and MI. Multivessel disease and a larger number of >50% lesions were associated with the need for repeat revascularization. In conclusion, STEMI was associated with a higher likelihood of in-hospital death than was NSTEMI, but long-term outcomes after PCI were independent of MI type. At 1 year, associated co-morbidities were strongly associated with death and MI, whereas only angiographic characteristics predicted the need for repeat revascularization.