Whether all children brought to the emergency room with a first seizure and fever require lumbar puncture (LP) remains controversial. We reviewed the emergency room records of 241 children aged 6 months to 6 years who had this clinical picture. Five history and physical examination items discriminated between children with and without meningitis: a physician visit within 48 hours before the seizure; the occurrence of convulsions on arrival at the emergency room; a focal seizure; suspicious findings on physical and/or neurologic examination. Used in combination, these items (risk factors) identified all children with meningitis but would have spared 62% of children without meningitis the need for LP. In a decision analysis framework, they were as sensitive but more specific than LP in detecting children with meningitis. Most important, their negative predictive value was 100%.