BACKGROUND: The course of pediatric hypertrophic cardiomyopathy (HCM) is variable, and the indications for heart transplantation (HTx) are ill defined. This study investigated outcomes and risk factors for adverse outcomes after listing for HTx. METHODS: A multicenter, event-driven data registry of patients aged < 18 years listed for HTx between January 1993 and December 2007 was used. RESULTS: During the study period, 3,147 children were listed for HTx (mean age, 7.6 +/- 0.8 years). Of l,320 with CM at listing, 77 (6%) had HCM (61% boys; 79% white); 59% were United Network of Organ Sharing (UNOS) status I, 30% were receiving inotropes, 27% were ventilated, and 8% required extracorporeal membrane oxygenation. Arrhythmia had occurred in 27%, and 14% had failure to thrive. Within 1 year, 65% underwent HTx. Overall, 25 patients died after listing: 11 (14%) while waiting and 14 of 49 (29%) after HTx. Pre-HTx survival was lower for those listed at age < 1 year (p = 0.0005). Risk factors for death after listing included UNOS status 1 (p = 0.01) and younger age (relative risk, 2.3; p = 0.001). Late (10-year) survival after HTx for HCM patients was 47% vs 63% for non-CM patients within the database. CONCLUSIONS: Children with HCM listed for HTx age < 1 year and UNOS status 1 have the highest mortality awaiting HTx. A more rigorous identification of additional risk factors should be performed to better define timing of listing and which patient sub-group may derive optimal benefit from HTx.