AIMS: The objective of this paper is firstly to estimate the healthcare costs attributable to heart disease in Denmark using recently available data for 2002-05. Secondly, to estimate the attributable healthcare costs of lifestyle risk factors among heart patients, in order to inform decision making about prevention programmes specifically targeting patients with heart disease. METHODS: For a cohort consisting of participants in a national representative health interview survey, register-based information about hospital diagnosis was used to identify patients with heart disease. Healthcare consumption during 2002- 05 among individuals developing heart disease during 2002-05 was compared with individuals free of heart disease. Healthcare costs attributable to heart disease were estimated by linear regression with adjustment for confounding factors. The attributable costs of excess drinking, physical inactivity and smoking among future heart patients were estimated with the same method. RESULTS: Individuals with heart disease cost the healthcare system on average 3,195 (p<0.0001) per person-year more than individuals without heart disease. The attributable cost of unhealthy lifestyle factors among individuals at risk of heart disease was about 11%-16% of the attributable cost of heart disease. CONCLUSIONS: Heart disease incurs significant additional costs to the healthcare sector, and more so if heart patients have a history of leading an unhealthy life. Consequently, strategies to prevent or cease unhealthy lifestyle may not only result in cost savings due to avoided heart disease. Additional cost savings may be obtained because heart patients who prior to the disease led a more healthy life consume fewer healthcare resources.