BACKGROUND: The aim of this study was to investigate the cost-effectiveness of cardiac resynchronization therapy (CRT) in Denmark, Finland and Sweden. The analysis was based on the CARE-HF trial, a randomised clinical trial investigating the efficacy of adding CRT (n=409) to optimal pharmacological treatment (n=404) in patients with moderate to severe heart failure with markers of cardiac dyssynchrony. The average follow-up time was 29.4 months. METHODS: The health effects were measured in terms of quality-adjusted life years (QALYs) gained. Data on health care resource consumption from CARE-HF was combined with costs for CRT implantation and hospitalisation from university hospitals in Denmark, Finland and Sweden. Calculations were based on patients' expected life time. The expected device lifetime (6 years) was used for CRT, and no additional gains in clinical effects were assumed after the 6 years. RESULTS: The cost-effectiveness ratio per QALY gained was 4800 euros in Denmark, 3600 euros in Finland and 6700 euros in Sweden. The 95% confidence intervals for the cost per QALY gained varied between a lower limit of 1169 euros in Finland to an upper limit of 17,482 euros in Sweden. These values were all below the threshold for being cost-effective in Denmark, Finland and Sweden. CONCLUSIONS: The study indicates that CRT is a cost-effective treatment in Scandinavian health care settings compared to traditional pharmacological therapy and can therefore be recommended for routine use in patients with moderate to severe heart failure and markers of dyssynchrony.