Objective. All- terrain vehicle (ATV) injuries among children represent a significant and growing problem. Although state level analyses have characterized some aspects of pediatric ATV- related injuries, little information on the national impact on hospitalization is available. This study was designed to characterize more fully the patterns of injury, hospital length of stay, and hospital charges associated with ATV- related injuries, with a nationally representative sample. Methods. Analyses were based on the 1997 and 2000 Healthcare Cost and Utilization Project Kids’ Inpatient Database (KID). The KID is the only national, all- payer database of hospital discharges for children. KID data were weighted to represent all discharges from general hospitals in the United States. Discharges with external cause- of- injury codes consistent with off- road ATV related injuries were selected, and the affected population was described. Nationally representative rates of ATV- related injuries were calculated, and changes between 1997 and 2000 were documented. Results. An estimated 5292 children were hospitalized because of ATV- related injuries during the 2- year period, and hospitalizations increased 79.1% between 1997 and 2000. Rates of ATV- related hospitalization were highest among adolescent white male subjects, consistent with previous studies. Most patients had hospital lengths of stay of < 4 days (68% ), but 10% had stays of > 8 days. Injury severity varied considerably, with more than one third of patients sustaining moderate to severe injuries. Approximately 1% of hospitalizations resulted in in- hospital deaths. Total hospital charges for this injury mechanism were ＄ 74 367 677 for the 2- year study period. Most of these charges were paid by private insurers. Conclusions. This study provides evidence supporting recent substantial increases in childhood ATV- related injuries. The hospitalization impact of ATV- related injuries among children is considerable. Our data support the need for ongoing creative attempts to identify effective strategies to decrease ATV injuries among children. Objective-All-terrain vehicle (ATV) injuries among children represent a significant and growing problem. Although this level of analysis has been characterized some aspects of pediatric ATV-related injuries, little information on the national impact on hospitalization is available. This study was designed to characterize more fully the patterns of injury, hospital length of stay, and hospital charges associated with ATV-related injuries, with a nationally representative sample. Methods. Analyzes were based on the 1997 and 2000 Healthcare Cost and Utilization Project Kids’ Inpatient Database (KID The KID is the only national, all-payer database of hospital discharges for children. KID data were weighted to represent all discharges from general hospitals in the United States. Discharges with external cause- of- injury codes consistent with off-road ATV related injuries were selected, and the affected population was described. Nationally representative rates of ATV-related injuries wer e calculated, and changes between 1997 and 2000 were documented. Results An estimated 5292 children were hospitalized because of ATV-related injuries during the 2-year period, and hospitalizations increased 79.1% between 1997 and 2000. Rates of ATV- related hospitalization were highest among adolescent white male subjects, consistent with previous studies. Most patients had hospital lengths of stay of <4 days (68%), but 10% had stays of> 8 days. Injury severity varied considerably, with more than one third of patients sustainly moderate to severe injuries. Approximately 1% of hospitalizations resulted in in- hospital deaths. Total hospital charges for this injury mechanism were $ 74 367 677 for the 2-year study period. Most of these charges were paid by private insurers. Conclusions. This study provides evidence supporting early substantial increases in childhood ATV- related injuries. The hospitalization impact of ATV- related injuries among children is considerable. Our da tasupport the need for ongoing creative attempts to identify effective strategies to decrease ATV injuries among children.