OBJECTIVES: A cost-utility analysis was conducted alongside the Danish On-pump Off-pump Randomization Study (DOORS) based on the intention to treat principle. METHODS: A post hoc analysis of the problem of missing data was addressed by multiple imputation using the conditional Gaussian as well as the chained equation approach. Both methods where applied using two different models (representing a data-driven respectively a clinical reasoning selection strategy). RESULTS: The cost-effectiveness acceptability curve for the complete case analysis (n=779) showed 88 % probability of OPCAB being cost-effective at a threshold value of £30.000 per QALY. In analyses based on the conditional Gaussians approach and the chained equations approach to multiple imputation the results was 73-75 %. CONCLUSIONS: The result of the previously published complete-case analysis of the cost-effectiveness of OPCAB versus CCABG was reinforced by this post hoc analysis of the uncertainty due to missing data. The analysis showed that the conditional Gaussian approach and the chained equations approach produced similar results Evidence about the long term cost-effectiveness of OPCAB versus CCABG is warranted.