Thromboembolic events are a known complication of nephrotic syndrome in children. Intracardiac thrombi are a rare location for thrombus formation but can lead to severe clinical consequences.We report an intracardiac left atrial thrombus in a child with new onset steroid-resistant nephrotic syndrome and recently repaired atrial septal defect and cor triatriatum. The thrombus was successfully treated with surgical excision.Intracardiac thrombus is a rare but serious complication of nephrotic syndrome in children, especially in children with risk factors for potentially increased intracardiac thrombogenicity such as history of recent intervention.