While some fluoroquinolone antibiotics can cause QT prolongation and Torsades de Pointes (TdP), serious proarrhythmic effects from ofloxacin have not been reported. Here, we report a case of ofloxacin-induced Torsades de Pointes with abnormal ECG changes, mimicking acute myocardial infarction. A 68-year-old man developed syncope following hospital admission for the treatment of pulmonary tuberculosis. TdP and marked QT prolongation (QT=0.44 sec, QTc=0.62 sec) were noted, with no remarkable serum electrolyte abnormality. The QT prolongation was followed by ST segment elevation, mimicking acute myocardial infarction. After discontinuation of ofloxacin, the QT interval shortened to 0.336 sec (QTc=0.481 sec), with no recurrence of TdP, although the QT interval remained mildly elevated during the hospital course. From this case, we propose that care should be taken in the use of ofloxacin, especially in patients susceptible to TdP.