Objective: To describe the distribution of child maltreatment fatalities of children under 5 by age, sex, race/ethnicity, type of maltreatment, and relationship to alleged perpetrator using data from the National Violent Death Reporting System (NVDRS). Study design: Two independent coders reviewed information from death certificates, medical examiner and police reports corresponding to all deaths in children less than 5 years of age reported to NVDRS in 16 states. Results: Of the 1,374 deaths for children under 5 reported to NVDRS, 600 were considered attributable to child maltreatment. Over a half of the 600 victims of child maltreatment in this age group were under 1 year old, 59% were male, 42% non-Hispanic Whites, and 38% were non-Hispanic Blacks. Two thirds of child maltreatment fatalities in children under 5 were classified as being due to abusive head trauma (AHT), 27.5% as other types of physical abuse, and 10% as neglect. Based on these data, fathers or their substitutes were significantly more likely than mothers to be identified as alleged perpetrators for AHT and other types of physical abuse, while mothers were more likely to be assigned responsibility for neglect. Conclusions: Among children under 5 years, children under 1 are the main age group contributing to child maltreatment fatalities in the NVDRS. AHT is the main cause of death in these data. These findings are limited by underascertainment of cases and fair inter-rater reliability of coding. Practice implications: The findings suggest the need to develop and evaluate interventions targeting AHT to reduce the overall number of child maltreatment deaths in young children. These interventions should make special efforts to include fathers and their substitutes. (Contains 2 tables.)