Mechanical circulatory support (MCS) has become a fundamental therapy in the management of patients with severe cardiac disease or respiratory failure. In children, the two forms of MCS employed in the pediatric population are extracorporeal membrane oxygenation (ECMO) and ventricular assist device (VAD). These modalities have overlapping but distinct roles in the management of pediatric patients with severe and refractory cardiopulmonary compromise. In the last 10 years, the number of centers with the capability of supporting a child with ECMO has nearly doubled, and the number of children supported for cardiac, pulmonary, and extracorporeal cardiopulmonary resuscitation indications has exceeded 70,000. Additionally, the most recent Pedimacs data demonstrated 44 hospitals implanted 1031 ventricular assist devices in 856 patients under 19 years of age. Despite increasing experience, adverse events remain a significant concern for children undergoing both ECMO and VAD support, with over 56% of patients on VAD support suffering from at least a major bleed, infection, device malfunction, or neurological event, and even higher in children on ECMO. Herein we describe MCS in pediatrics with regard to patient selection, device options, management considerations, and outcomes.