This study aimed to determine athletic trainer compliance with emergency medicine and athletic training evidence-based guidelines for the on-the-field management of common pediatric sports-related injury and illness. A questionnaire was distributed electronically to selected members of the National Athletic Trainer Association. The questionnaire included 10 clinical scenarios describing common sports-related injury/illness (closed head injury, cervical spine injury, blunt chest injury, blunt abdominal injury, ankle injury, knee injury with laceration, heat-related illness). On-the-field management decisions for each scenario were compared with selected emergency medicine and athletic training guidelines. Analysis was performed on 564 completed questionnaires (9% response rate). Responders were compliant with practice guidelines for both emergency medicine and athletic training except for blunt chest trauma with tachycardia, closed head injury with loss of consciousness, closed head injury with repetitive speech, closed head injury with a fall higher than 5 feet, cervical spine injury with paresthesias, and heat-related illness with persistent symptoms. Discrepancies between emergency medicine and athletic training guidelines included closed head injury with repetitive speech, closed head injury and height of fall, closed head injury and unequal pupils, and cervical spine injury with neck pain and paresthesias. Based on our sample, athletic trainers were compliant with many guidelines supported by both emergency medicine and athletic training. We identified several deficiencies in the availability of evidence-based guidelines and discrepancies between these guidelines and athletic trainer responses. To provide optimal care to pediatric athletes who sustain injury or illness, emergency medicine and athletic training organizations should collaborate to improve these discrepancies.