A seventeen-year-old male presented with severe substernal chest pain after an episode of upper respiratory tract infection. On clinical grounds, a diagnosis of myocarditis was established. He had a peak troponin I level as high as 40.4 ng/dl but interestingly with no abnormal wall motion and normal ejection fraction in echocardiography. Coronary artery disease was excluded with normal coronary angiography. Diagnosis of myocarditis was confirmed with cardiac MRI. After one month, patient had no complaint and ejection fraction were still normal. Our case emphasizes that the troponin levels predict neither the early nor the late outcome of the left ventricular functions in myocarditis, therefore serum troponin I may not be helpful in determining the prognosis of patients with myocarditis.