In contrast to computed tomography, ultrasound can be performed without radiation exposure, repeatedly performed by the patients’ bedside. Hence, in this case series, we describe the evaluation of complications including hematoma, superficialsurgical site infection, mediastinitis, and pseudoaneurysm associated mediastinitis using ultrasound in pediatric patients after cardiovascular surgery. To our knowledge, no previous reports have evaluated such complications using ultrasound. Ultrasound may be useful for the early diagnosis of these complications, and in the selection of subsequent examinations such as computed tomography, resulting in the early initiation of intervention.