Running for exercise is a popular way to motivate children to be physically active. Running-related injuries are well studied in adults but little information exists for children and adolescents. Through use of the National Electronic Injury Surveillance System database, cases of running-related injuries were selected by using activity codes for exercise (which included running and jogging). Sample weights were used to calculate national estimates. An estimated 225 344 children and adolescents 6 to 18 years old were treated in US emergency departments for running-related injuries. The annual number of cases increased by 34.0% over the study period. One third of the injuries involved a running-related fall and more than one half of the injuries occurred at school. The majority of injuries occurred to the lower extremities and resulted in a sprain or strain. These findings emphasize the need for scientific evidence-based guidelines for pediatric running. The high proportion of running-related falls warrants further research.