It has been reported that myocardial bridging may be associated with myocardial ischemia, myocardial infarction, vasospasm, cardiac arrhythmia and sudden death. However, the mechanism whereby ischemia occur as a consequence of myocardial bridging remains unclear. Recently we experienced a case of myocardial infarction in a patient with myocardial bridging and atrial fibrillation. A 66-year-old man presented with severe chest pain. His ECG showed ST elevation in V3-V5 and atrial fibrillation with rapid ventricular response. He underwent coronary angiography, which revealed a thrombus in the distal portion of the myocardial LAD bridge. He was treated with antiplatelet agents, heparin, tirofiban and amiodarone and beta-blocker without percutaneous coronary intervention. Five days later, his clinical condition was recovered and follow-up coronary angiography revealed markedly improved blood flow of the left anterior descending artery. The previous thrombus had disappeared.