Objective: To evaluate the construct validity of the Turkish version of the EQ-5D in patients with acute coronary syndrome. Methods: The study was conducted as a cross-sectional study at the Trakya University Hospital between February and May 2008. All patients completed the Turkish version of the EQ-5D and MacNew heart-related quality of life scale. Construct validity of the EQ-5D was assessed according to relationships with MacNew subscales by using Spearman rank correlation and multiple linear regression analyses. Results: One hundred and twenty-two patients responded to the instruments. Mean age was 62.9±9.3 years and male gender (88 or 72.1%) was dominant. Mean score of the EQ-5D index was 0.79±0.32, while the global score of MacNew was 5.01±1.16. The correlation coefficients of the EQ-5D index score with the MacNew subscales ranged from 0.557 to 0.721, with EQ-5D VAS score ranging from 0.297 to 0.484 (p<0.001 for all of them). According to the stepwise regression model MacNew global score was found to be significantly effective factor on EQ-5D index score (β=0.188; 95% CI: 0.152-0.224; p<0.001). Conclusion: The Turkish version of the EQ-5D-based utility score seems to be a valid instrument in the assessment of quality of life studies in patients with acute coronary syndrome.