long QT and related ventricular arrhythmias may complicate the evolution of Eating Disorders (ED) but duration of QT interval and prevalence of long QT in large series of ED patients has not been reported.QT intervals were measured in 100 consecutive ED patients (anorexia nervosa, bulimia nervosa or mixed) in lead II, V2 and V5 and corrected using Bazett’s formula. 95 healthy subjects matched in age and gender forms the control group.mean age was 30±12 yo and 93% were females. Mean Body Mass Index (BMI) was 16.9±3kg/m 2 . Heart rate was significantly lower in patients with ED (64±14 bpm) compared to controls (78±15 bpm) (p<0.0001).QT were significantly longer in ED patients than in controls in leads II (384±33 vs 366±32, p=0.0003), V2 (377±37 vs 367±35ms, p=0.04) and V5 (381±34 vs 365±30ms, p=0.0005). Corrected QT were significantly shorter in patients with ED compared to controls in leads II (389±28 vs 412±28ms), V2 (383±27 vs 413±32ms) and V5 (387±26 vs 410±28ms) (p<0.0001 for each comparison). None of the ED patients had a corrected QT >480 msec (max 464ms). U wave was present in 16% of patients with ED and 4% in controls (p=0.006).BMI and heart rate were negatively correlated with QT in univariate analysis. After adjustment for BMI and heart rate, QT was significantly lower in patients with ED in leads II, V2 and V5 (p<0.05).Corrected QT tended to be increased in ED patients receiving drugs known to increase QT (p = 0.1). QT was negatively correlated to plasma magnesium level (p = 0.01), to calcemia (p = 0.06) and to plasma albumin (p = 0.004). QT was not associated to plasma potassium level. QT did not differ between the different types of ED.No patient did present with major event before inclusion or during follow-up.QT durations were found normal in patients with ED and were even shorter than in controls when corrected or adjusted for heart rate. QT was only related to BMI, calcium and magnesium plasma levels.