Phospholipid antibodies (lupus anticoagulant, cardiolipin) are associated with a syndrome of repeated fetal loss. Mothers with phospholipid antibodies are currently being treated with either prednisone, aspirin, or heparin to prevent fetal death. We describe a neonate whose mother had cardiolipin antibody and recurrent fetal loss and was treated with prednisone and aspirin. Thrombosis was noted in placental fetal vessels. Thromboses developed in the infant's aorta, left renal artery, middle cerebral artery, and superior sagittal sinus. Infants of phospholipid-positive mothers may have vascular thrombosis and should be carefully monitored for signs of thromboembolism.