We report a case of a 70-year-old woman with Tako-tsubo syndrome admitted to the hospital with typical chest pain and electrocardiogram changes in anterior precordial leads suggesting acute coronary syndrome. Coronary angiography demonstrated normal coronary artery and left ventriculography the typical apical ballooning of Tako-tsubo syndrome. Transthoracic echocardiographically derived coronary flow velocity reserve by adenosine was lower than normal (1.54) in the acute phase and improved after 1 month (2.68). At this time, electrocardiogram normalization also occurred. Our report supports the hypothesis that coronary microvascular dysfunction might be a determinant of Tako-tsubo syndrome.