We presented a four-year-old girl with Tay-Sachs disease who had thrombus in the right atrium. The patient was admitted to hospital with cardiopulmonary arrest and 
aspiration pneumonia was diagnosed. Intracardiac thrombus was detected during rutine echocardiographic examination. There was no underlying genetic prothrombotic predisposition in this patient. The guidelines of treatment for intracardiac thrombus in children are lacking in the literature andthe experience in managing these patients is limited. We aimed to to discuss the treatment approaches to intracardiac thrombi and to emphasize that, development of intracardiac thrombus is common in critically ill children and can be treated successfully by non-invasive anticoagulation with heparin.