Objective: Studies of high-risk pediatric cardiac transplant recipients are lacking. The purpose of this study is to evaluate early posttransplant survival in high-risk pediatric patients. Methods: The United Network for Organ Sharing (UNOS) provided de-identified patient-level data. The study population included 3502 recipients aged less than 21 years who underwent transplantation from January 1, 1995, through December 31, 2005. Recipients were stratified on the basis of the presence or absence of high-risk criteria: pulmonary vascular resistance index greater than 6 Wood units/m2 (n = 285, 8.1%), creatinine clearance less than 40 mL/min (308, 8.8%), hepatitis C positivity (33, 0.9%), donor/recipient weight ratio less than 0.7 (80, 2.3%), panel reactive antibody greater than 40% (235, 6.7%), retransplantation (235, 6.7%), and age less than 1 year old (840, 24.0%). Results: Overall, 1575 (45.0%) patients met at least one high-risk criterion. Higher numbers of high-risk criteria in a patient were correlated with increased 30-day mortality (0 high-risk criteria: 5.2%; 1 criterion: 7.9%; 2 criteria: 12.9%; and 3 or more criteria: 25.0%; P < .0001) and poor long-term survival (P < .0001). Among patients with high-risk criteria, a simplified scoring scale accurately predicts both 30-day and contingent 1-year mortality (P < .0001). Conclusions: Individually, the effect of high-risk criteria on posttransplant survival varied; however, increasing numbers of criteria in a patient resulted in a cumulative increase in mortality. A scoring scale allows for the prediction of approximate mortality rates after transplantation. These findings suggest that recipient criteria for transplantation should focus on the number of high-risk criteria as well as clinical status, rather than the presence or absence of a single risk factor. © 2008 The American Association for Thoracic Surgery.