This study compared the presentation (symptoms and signs), treatment, and outcome of 1,097 consecutive patients (851 men and 246 women) from the Myocardial Infarction Triage and Intervention (MITI) Project Registry with confirmed acute myocardial infarction (AMI), all of whom were initially evaluated in the prehospital setting, met clinical criteria for possible thrombolysis, and were followed throughout their hospital course. Women were older than men and had a higher prevalence of known cardiovascular risk factors, including systemic hypertension and congestive heart failure. The presentation of AMI with respect to symptoms, delay, and hemodynamic and electrocardiographic findings was for the most part indistinguishable between mean and women. Women appeared "undertreated" early in the course of AMI and were half as likely as men to undergo acute catheterization, angioplasty, thrombolysis, or coronary bypass surgery (odds ratio 0.5 [0.3 to 0.7]). The risk for hospital mortality in women was almost twice that for men (odds ratio 1.95 [1.01 to 3.8]). Hospital mortality after AMI was also independently predicted by older age, early evidence of hemodynamic instability, and an intraventricular conduction abnormality on the initial electrocardiogram. Although similar in its presentation, AMI in women is not as aggressively treated, and results in a less favorable outcome than in men. Gender as well as nongender-specific risk factors are important in assessing risk and the likelihood of early intervention after AMI.