Epidemiological and clinical studies attribute to Chlamidia pneumoniae infections a pathogenetic role in atherosclerotic vascular lesions. We report two patients in whom this infection was followed by acute coronary events. A 51 years old male presented with a right lower lobe pneumonia and a positive immunofluorescence serology for Chlamidia pneumoniae, with a IgM titer of 1/64. On the second day of evolution, he experienced an acute myocardial infarction. A coronary arteriography demonstrated a 80% obstruction of anterior coronary artery and an angioplasty was performed. A 84 years old male was admitted with a right lower lobe pneumonia and a positive serology for Chlamidia pneumoniae, with an IgM titer of 1/32. On the fourth day of evolution, he developed unstable angina with electrocardiographic changes. A coronary arteriography demonstrated a three vessel disease. In both cases, a tight chronological association was observed between Chlamidia pneumoniae infection and acute coronary events.