Background The purpose of the present study was to investigate the elastic characteristics of the aorta in patients with coronary ectasia (CE) and the relationship between these characteristics and echocardiographic left ventricular (LV) diastolic functions. Methods and Results In the first group there were 35 patients with CE, the second group consisted of 35 patients with coronary artery disease (CAD) and the third group consisted of 35 patients with normal coronary arteries. Echocardiographic investigation was carried out for the assessment of the LV diastolic functions. Aortic strain, β index and aortic distensibility were used as aortic elasticity parameters. LV diastolic functions were impaired in both the ectasia group and the CAD group as compared with patients with normal coronary arteries. Beta index and aortic distensibility measurements were similar between the CAD and CE groups. The values obtained for aortic strain, β index and aortic distensibility were lower in the CAD and ectasia groups when compared with the values of the normal group. On performing the stepwise linear multivariable analyses, aortic elastic parameters have been determined to possess the strongest diagnostic power for LV diastolic functions. Conclusions The results of the current study show that stiffness parameters of aorta are impaired in the patients with CE as in the patients with CAD. The increase in aortic stiffness might be responsible for LV diastolic dysfunction. (Circ J 2007; 71: 506 - 510)