The objective of this study was to evaluate in-hospital and 1-year outcomes of patients with acute coronary syndrome (ACS) enrolled in clinical studies. Among patients included in the Canadian ACS Registries, patients enrolled in clinical studies (n = 883, 13.4%) were compared with patients who were not enrolled. Enrolled patients were younger, more likely to be smokers, had less diabetes, less hypertension, less previous myocardial infarction, and less previous percutaneous coronary intervention and coronary artery bypass grafting. Enrollment in clinical studies was higher in patients with ST-elevation and ST-depression ACS. Furthermore, patients enrolled had more coronary interventions (percutaneous coronary intervention and coronary artery bypass grafting) and received more evidence-based therapies such as aspirin and statins. Unadjusted event rates were significantly higher in patients not enrolled in clinical studies: in-hospital death 2.4 versus 1.1% (P = 0.02), and 1-year death 9.2 versus 6.1% (P = 0.003), and death or myocardial infarction 16.1 versus 13.8% (P = 0.09). After multivariable analysis, enrollment in clinical studies showed a trend towards decreased in-hospital and 1-year death. Patients with ACS in Canada who participate in clinical studies are more likely to receive evidence-based therapies and interventions throughout hospitalization. After multivariable analysis, enrollment in a clinical trial may also contribute to better in-hospital and 1-year outcome.