BACKGROUND: P-wave dispersion (Pd), corrected P-wave dispersion (Pdc), QT-wave dispersion (QTd), and corrected QT-wave dispersion (QTdc) parameters were not assessed in Turner Syndrome (TS) before. The aim of this study is to investigate the cardiac arrhythmogenic potential in patients with TS. METHODS: Thirty-one patients with TS and 30 healthy women were enrolled in the study. For this purpose 12-lead electrocardiogram (ECG) and 24-hour ambulatory ECG recordings were performed. RESULTS: Pd, Pdc, QTd, and QTdc were significantly higher in patients with TS. On 24-hour ambulatory ECG recording, the mean heart rate (HR) was higher, while the mean of all RR intervals between normal beats (MeanNN), the standard deviation of all the RR intervals (SDNN), the square root of the mean of the squared differences of two consecutive RR intervals (rMSSD), and the percentage of the beats with consecutive RR interval difference more than 50 milliseconds (pNN50) were lower in TS. CONCLUSION: There were significant increases in Pd, Pdc, QTd, and QTdc in patients with TS and they may be features of the disease. The frequency of supraventricular arrhythmias was increased. There also was a significant deterioration of sympathetic and parasympathetic components of autonomic function as assessed by heart rate variability (HRV) in Turner patients.