Findings from this study on the cost of pediatric abusive head trauma in New Zealand revealed that hospital costs totaled $NZ2.4 million, child protection costs totaled $NZ1.56 million, police investigations totaled $NZ1.84 million, criminal trial costs totaled $NZ3.2 million, punishment of offenders costs totaled $NZ4.4 million, and community rehabilitation costs totaled $NZ2.9 million. In addition, projected education costs for disabled survivors totaled $NZ2.45 million, and the cost of projected lifetime care was $NZ33.6 million, with total costs projected to be $NZ52.4 million, or an average of $NZ1.008 million per child. This study was conducted to determine the benefit of establishing a national primary prevention program to deal with pediatric abusive head trauma in New Zealand, given the current level of costs associated with the problem. Data for the analysis were obtained from 52 cases of pediatric abusive head trauma that were treated at a hospital in Auckland, New Zealand over a 5-year period. The direct costs of the injuries were determined and a cost-benefit analysis was conducted to inform the decision for the development of a national primary prevention program. The following costs were evaluated: hospital care, community rehabilitation, special education, investigation and child protection, criminal trials, punishment of offenders, and life-time care for moderate or severe disability. The study's findings indicate that pediatric abusive head trauma is very expensive and that a strong positive economic argument exists for the development and implementation of a national primary prevention program. Study limitations are discussed. Figure, tables, and references