OBJECTIVE: In contrast to effectiveness of health care interventions, health states preferences might not be transferable between countries. A frequently used instrument to measure health-related quality of life is the EQ-5D, which has been developed to compare preferences across countries. Although the impact of using any of the fifteen national EQ-5D value sets on utility estimates is known, the impact on the incremental utility is unknown so far. METHODS: First, the relative influence of the EQ-5D domains on the utility estimate was assessed for each of the fifteen currently existing value sets. Second, two health states (21232 and 33321) were selected for further analyses. With the help of the two hypothetical health states we determined the influence of one or two point deteriorations of the health states. Based on this, the fifteen value sets were used to calculate incremental utility scores. RESULTS: Differences can be perceived between the value sets and between the valuation methods in the preferences for the domains of the EQ-5D. The utility scores of health states show that the differences between the value sets are substantial. Next to that, the dissimilarities between the increments of the deteriorations of the health sets are large, independent of which valuation method is used. CONCLUSION: All results indicate that the differences between the value sets are considerable and should not be ignored. The magnitudes of the coefficients of the domains vary in a great extent, which causes dissimilarities when calculating the incremental utilities. As a consequence it can be concluded that the utility scores are not transferable across countries.