A Consensus Development Conference on Febrile Seizures was held at the National Institutes of Health on May 19-21, 1980. The purpose of the Conference was to bring together practicing physicians, research scientists, consumers, and others in an effort to reach general agreement on the risks of sequelae in children with febrile seizures and to compare them with the potential risks and benefits of prophylaxis with anticonvulsants. On the first two days of the meeting, a consensus development panel and members of the audience reacted to evidence presented on the following questions: (1) What is a febrile seizure? (2) What are the risks facing the child who has a febrile seizure? (3) What can chronic or intermittent prophylaxis accomplish in reducing those risks? (4) What are the potential risks of prophylaxis, using the available forms of therapy? (5) What is a rational approach to management of children with febrile seizures? Which children should be considered for prophylaxis? (6) Are further clinical, experimental, or epidemiologic studies necessary? The members of the Consensus Development Panel represent the disciplines involved with treating and evaluation of management of children with febrile seizures. The physicians were nominated for their role on the panel by four specialty medical associations: the American Academy of Pediatrics, the American Academy of Neurology, the American Academy of Family Physicians, and the Child Neurology Society. The panel met following the formal presentations and discussions to examine and debate the issues, based on the evidence presented. This summary is the result of these deliberations.