To present new estimates of the average lifetime costs per child maltreatment victim and aggregate lifetime costs for all new child maltreatment cases incurred in 2008 using an incidence-based approach. This study used the best available secondary data to develop cost per case estimates. For each cost category, the paper used attributable costs whenever possible. For those categories that attributable cost data were not available, costs were estimated as the product of incremental effect of child maltreatment on a specific outcome multiplied by the estimated cost associated with that outcome. The estimate of the aggregate lifetime cost of child maltreatment in 2008 was obtained by multiplying per-victim lifetime cost estimates by the estimated cases of new child maltreatment in 2008. The estimated average lifetime cost per victim of nonfatal child maltreatment is $210,012 in 2010 dollars, including $32,648 in childhood health care costs; $10,530 in adult medical costs; $144,360 in productivity losses; $7,728 in child welfare costs; $6,747 in criminal justice costs; and $7,999 in special education costs. The estimated average lifetime cost per death is $1,272,900, including $14,100 in medical costs and $1,258,800 in productivity losses. The total lifetime economic burden resulting from new cases of fatal and nonfatal child maltreatment in the United States in 2008 is approximately $124 billion. In sensitivity analysis, the total burden is estimated to be as large as $585 billion. Compared with other health problems, the burden of child maltreatment is substantial, indicating the importance of prevention efforts to address the high prevalence of child maltreatment.