Acute myocardial infarction during pregnancy and postpartum period is rare. A case of a 29-year-old female who developed acute myocardial infarction during postpartum period is presented. Coronary angiography revealed thrombosis of a coronary artery aneurysm of the marginal branch. The patients was treated conservatively and during 5 months of follow-up the clinical course was uneventful.