To investigate intrinsic vascular abnormalities of the ascending aorta before adulthood in Turner syndrome patients (TS), we compared 25 adolescent TS patients (mean age 14.6 ± 3.4 years) and 16 healthy controls from a university hospital. Blood pressure and other vascular indices were evaluated using echocardiography such as aortic strain, stiffness index, distensibility, and pulse wave velocity. Aortic strain (0.1237 vs. 0.1865, respectively; P = 0.003) and aortic distensibility (0.0049 vs. 0.0081, P = 0.002) were significantly lower in the TS group than in the controls. The fractional area change on velocity vector imaging was also lower in TS patients (29.05 vs. 36.19, P = 0.002). These findings were still observed after adjustment for age, body mass index, and systolic blood pressure. The aortic stiffness index was greater in the TS patients than in the control group (6.79 vs. 3.34, P = 0.02). The pulse wave velocity and ascending aorta diameter did not significantly differ between the TS and control groups. Blood pressures were significantly higher in the TS patients than in the controls (systolic, 120.4 vs. 108.4 mmHg, P = 0.001; diastolic 71.5 vs. 61.7 mmHg, P < 0.001). Although the dimensional changes in the aorta were not clearly observed in adolescents with TS, the elastic properties of the aorta were significantly decreased in TS patients as compared to control subjects.