INTRODUCTION: The Danish Heart Registry (DHR) keeps track of all coronary angiographies (CATH), percutaneous coronary interventions (PCI), coronary artery bypass grafting (CABG), and adult heart valve surgery performed in Denmark. DHR is a clinical database established in order to follow the activity and quality of the procedures mentioned. MATERIALS AND METHODS: Information concerning each procedure, age, gender, and co-morbidity of the patient was collected. Each patient was followed with respect to survival for 30 days by linkage to the central personal registry in Denmark. Mortality was estimated by the Kaplan-Meier method and comparisons of 30-day mortality between centres were carried out in Cox proportional hazard models. RESULTS: The mortality within 30 days after PCI was 3.2% and closely related to the indication for PCI: ST-elevation myocardial infarction (STEMI) 6.8%; non-STEMI & unstable angina pectoris 1.9% and stable angina pectoris 0.5%. The 30-day mortality after PCI on the indication STEMI did not differ between the five centres, P=0.30. Mortality within 30 days after isolated CABG was 2.6% and was closely related to the EuroSCORE. The 30-day mortality after isolated CABG did not differ between the five centres, P=0.12. CONCLUSION: The 30-day mortality was closely related to the indication for PCI and the EuroSCORE for patients undergoing CABG. There were no significant differences in 30-day mortality between centres after either primary PCI or isolated CABG.