Factors associated with aortic dilation and dissection in patients with Turner syndrome (TS) remain unclear. We assessed magnetic resonance imaging-based aortic diameters at nine predefined anatomic positions and examined associations of increased aortic diameters with B-type natriuretic peptide (BNP), A-type NP (ANP), growth hormone treatment, insulin-like growth factor 1 (IGF1), and estrogen status. Forty-seven patients with TS aged 7.3-21 years and 34 healthy peers were enrolled in this study. Aortic diameters were higher in patients with TS at three positions than in controls (p < 0.05). History of GH treatment, pubertal status, and serum estradiol levels were not associated with increased aortic diameters. Patients with TS had higher plasma BNP and ANP levels than controls. BNP and IGF1 were independently associated with the increase in aortic diameters in TS at three positions of the ascending aorta (R (2) = 0.361-0.458, p < 0.05 for all). At two positions of the descending aorta, only BNP emerged as an independent variable (R (2) = 0.130-0.139, p < 0.05). We conclude that young, normotensive patients with TS had greater aortic diameters at several positions than healthy controls. BNP and IGF1 were independently associated with increased aortic diameters in TS.