The only systematic collection of cardiovascular (CV) deaths in children resides in the database derived from the Case Reporting System of the National Center for the Review and Prevention of Child Deaths (NCRPCD). We describe the process used to develop an analytical data set to inform our understanding of CV deaths in children from this database.Twenty-five states reporting natural CV deaths during 2005 to 2009 were contacted. Sixteen states agreed to participate. Cases experienced a natural CV death and were 0 to 21 years. Challenges to building a final analytical data set were identified and included reclassification, recategorization, and the development of new variables from existing data, including an algorithm to identify sudden cardiac deaths.The final data set included 1,098 cases. Missing data comprised a mean of 41.7% for most key variables. Cardiovascular cases were aged 4.8 ± 6.6 years; 55.3%, ≤1 year, 24.6%, ≥10 years; male, 58%; white, 70.5%; black, 22.3%; and Hispanic, 19.5%.This manuscript provides the first description of the natural CV death data set from the NCRPCD. We identify potential beneficial changes in the NCRPCD Case Reporting System and review process. Analysis of these data will help determine characteristics of CV deaths and allow the assessment of risk factors that can be used to prevent CV death in the young. The rate of CV death can be lowered using knowledge of associations that can be gleaned from this robust database. Best practices for prevention hold promise for a future with fewer deaths that will need to be reviewed.