Background/aim: Myocarditis in the acute phase usually presents with sinus tachycardia but many other arrhythmias might be seen as well. In this study we aimed to investigate repolarization abnormalities in baseline ECG of patients with myocarditis for the first time.Materials and methods: Thirty patients diagnosed with myocarditis and 25 healthy age-matched controls were included. Two different cardiologists measured corrected QT (QTc), QT dispersion (QTd), QT peak (QTp), T wave peak to T wave end (TpTe), TpTe/QT ratio, and TpTe/QTc ratio in 12-lead ECG.Results: When compared with the control group, QTp (P: 0.021), QT (P: 0.003), TpTe (P < 0.001), TpTe/QTc ratio (P < 0.001), and TpTe/QT ratio (P: 0.005) were significantly higher in patients with myocarditis. A comparison of receiver operating characteristic (ROC) curves was conducted using the Hanley and McNeil method. The area under the curve (AUC) of the electrocardiographic characteristics QT (AUC: 0.736; 95% CI [0.600-0.846]), QTP (AUC: 0.680; 95% CI [0.540-0.799]), and TpTe (AUC: 0.771; 95% CI [0.638-873]) and TpTe/QTc (AUC: 0.774; 95% CI [0.641-0.876]) and TpTe/QT (AUC: 0.726; 95% CI [0.589-0.838]) in myocarditis were not significantly different from each other but all of them were different from 0.5.Conclusion: Baseline ECGs of patients with myocarditis were associated with repolarization abnormalities. These novel findings may be one of the reasons underlying arrhythmic events in patients with myocarditis.