Cardiac arrest has been described in children with diabetic ketoacidosis (DKA). Aim. To evaluate QTc and QTd in type 1 diabetic children with DKA. Methods. Twelve-lead ECG was done to 30 type 1 diabetic children with DKA at presentation and recovery. Corrected QT interval and QT dispersion (QTd) were assessed. Results. QTc and QTd mean values were significantly decreased in patients after than before DKA recovery (P < 0.01). Procedure. Sixteen patients (53, 3%) had prolonged QTc during DKA (range 451-538 ms) that dropped to one patient after recovery, his QTc (453 ms) returned to normal 5 days after hospital discharge. Nineteen patients (63.3%) had prolonged QTd (>50 ms) that dropped to three after recovery. The fact that three patients had normal QTc but prolonged QTd increases the privilege of QTd over QTc as a better marker for cardiac risk in those patients. Anion gap was significantly associated with QTc and QTd prolongation (P < 0.0001). Patients had no electrolyte abnormalities or hypoglycemia to account for QTc or QTd prolongation. Conclusion. Prolonged QTc and QTd frequently occur in DKA positively correlated to ketosis. Cardiac monitoring for patients with DKA is mandatory.