A 42-year-old man experienced chest discomfort after being struck by a low-speed flying object. Two weeks after the accident, the patient complained of severe shortness of breath accompanied by ankle edema. Chest X-ray indicated acute pulmonary edema and left ventricular enlargement. There were Q waves and flat T waves in the precordial ECG leads. Echocardiography revealed dyskinesis in the interventricular septum, hypokinesis in the anterior left ventricular wall, and severe impairment of left ventricular function. A coronary angiogram showed 90% stenosis of the proximal left descending coronary artery. Subsequent medical therapy with diuretics and enalapril led to significant improvement in ventricular function and the patient's symptoms. We conclude that a mild blunt chest trauma can cause myocardial infarction and severe congestive heart failure. Careful investigations into myocardial ischemia or infarction and a close follow-up should be conducted in all patients presenting with a blunt chest trauma.