Use of all-terrain vehicles (ATVs) in agriculture appears to be growing. Purpose: To provide estimates of ATV ownership and exposure on US farms and an overview of injuries to youths as a result of ATV use on the farm in 2001. Methods: Analysis of the National Institute for Occupational Safety and Health and US Department of Agriculture 2001 Childhood Agricultural Injury Survey. These data, collected via telephone surveys, provide information on nonfatal injuries that occurred to youths younger than 20 years living on US farms during 2001. The injuries included both occupational and nonoccupational incidents. Findings: Of an estimated 1.1 million youths living on farms, 36% had operated an ATV in 2001. Youths younger than 16 years were more likely to have operated an ATV than a tractor on these farms. An estimated 2,246 nonfatal ATV-related injuries occurred to youths younger than 20 years on US farms during 2001. The majority of these ATV injuries (1,668, 74%) occurred to youths identified as members of the household. Males accounted for 1,145 (69%) of the ATV injuries to household youths. The majority of the injuries were to youths aged 10-15 years (1,170, 70%). Most ATV injuries were the result of recreational activities (970, 58%). In addition, many of these injury events involved youths riding without helmets and using ATVs that were larger than the recommended size for their age.