Practice guidelines and performance measures are critical elements of an effective quality improvement process for emergency medical services for children (EMSC). Practice guidelines address the clinical management of individual patients, and performance measures assess the quality of care delivered to a population. The public and private sectors have invested considerable resources in developing practice guidelines and performance measures to improve the quality of health care services. As organizations continue development efforts, health care professionals who are actively involved in emergency care must collaborate to develop guidelines that address the unique physiologic, psychologic, and cultural needs of children. The Emergency Medical Services for Children Managed Care Task Force recommended the development of a series of white papers to focus on issues related to practice guidelines and performance measures in EMSC. The Maternal and Child Health Bureau, Health Resources and Services Administration, the National Highway Traffic Safety Administration, and the Robert Wood Johnson Foundation jointly sponsored the project. The paper was developed by a panel selected from a pool of experts in managed care, quality improvement, and emergency medical services. After a review of the literature, the panelists met to discuss critical issues related to practice guidelines and performance measures in EMSC. The panelists developed recommendations that can serve as resources for managed care organizations, health care providers, professional associations, and governmental policy makers. The panel recognized the lack of nationally recognized pediatric emergency care guidelines and performance measures and called for immediate action in these areas.