In many adult cardiac programs, intracorporeal mechanical circulatory support has become a routine treatment for end-stage cardiac failure. For the pediatric population, options are often limited by a small body habitus. Even when an adolescent's weight may suggest adequate space for device implant, most intracorporeal adult devices remain too large for adolescents. The Thoratec HeartMate II (HM II) (approved by the FDA in April of 2008) is a small, noiseless device that is easily operated and monitored. By having an uncomplicated operating system and small percutaneous drive line, the HM II provides an opportunity for these patients to aggressively rehabilitate to become a better transplant candidate and also provides the potential to be discharged home. The two youngest patients ever to utilize the HM II are also the first two cases of using the HM II at a freestanding pediatric hospital. A 12-year-old, 53 kg, girl with dilated cardiomyopathy was supported for 85 days before receiving her heart transplant. The second patient, a 13-year-old, 149 kg, Hispanic male suffering from morbid obesity and dilated cardiomyopathy, was supported for 128 days. The HM II allowed for rehabilitation and nutritional education, resulting in this patient losing 50 kg before heart transplant. Despite both of these patients' size, their thoracic cavities were that of a preadolescent and thus techniques were developed to avoid morbidities like chest wall abrasion and bleeding. Because of differences between adult and pediatric patients and institutions, these cases provided unique challenges. However, as pediatric device therapy is now maturing, pediatric programs such as Texas Children's Hospital have begun to develop strategies for mechanical support that factor in patient's size and need for long-term or temporary support, utilizing the growing number of devices (i.e., Jostra Rotoflow, Tandem Heart PTVA, Thoratec CentriMag, Berlin Heart EXCOR, etc.) that are now available to children.