Background: The CardioMEMSTM HF system has been successfully used in adults for management of heart failure. Reports of use in pediatric patients are rare. In this case series, we aim to describe the novel use of this device in a large academic pediatric center. Methods: Retrospective, single center, descriptive case-series. Results: At time of abstract completion, our center has successfully implanted the CardioMEMSTM HF systems in four patients. The age at implantation ranged from 11 to 17 years, weight at implantation ranged from 27-73 kg. Vascular access for implantation was via a femoral vein in all patients. Three were implanted into the left lower pulmonary artery (PA) and one was implanted into the left pulmonary artery. The PA size ranged from 8.5-13.8 mm. There were no adverse events with implantation. The PA pressures reported by the device ranged from 14-20 mmHg and correlated with invasive monitoring. The pulmonary vascular resistance ranged from 2.3-8.7 iWu. Patient #1 had a diagnosis of Shone’s complex, and developed left ventricular diastolic dysfunction and resultant pulmonary artery hypertension (PAH). She was supported with a Berlin LVAD and subsequently underwent cardiac transplantation. Patient #2 had restrictive cardiomyopathy and paroxysmal junctional tachycardia with difficult to manage fluid status. This patient ultimately underwent cardiac transplant. Patient #3 had congenital aortic valve stenosis with concern of left atrial hypertension and ultimately underwent transplantation. Patient #4 had chemotherapy induced dilated cardiomyopathy and underwent Heartmate III LVAD implantation and is currently requiring milrinone for ongoing heart failure management. In all cases the CardioMEMSTM HF was successfully implanted and gave valuable diagnostic information in the management of PAH, fluid management and heart failure. Conclusions: This single center case series describes the early successful use of CardioMEMSTM HF system to aid management of PAH, fluid management and heart failure in a diverse pediatric population.