Myocardial infarction in the perinatal period is a rare occurrence, usually associated with congenital heart lesions or isolated coronary artery abnormalities. In the absence of structural heart disease the most common etiologies are intrauterine asphyxia and thromboembolic coronary occlusion. A paradoxical embolus usually arises from a thrombus in the ductus venosus or umbilical vein and reaches the coronary circulation via normal fetal circulatory pathways. We describe a case of perinatal myocardial infarction due to thromboembolism of the coronary artery secondary to an intrauterine renal vein thrombosis. The difficulties encountered in making an accurate premortem diagnosis are emphasized as well as the poor prognosis of myocardial infarction in the perinatal period.