We report the data of 878 selected children between 1 month and 6 years, presenting a first episode of seizure with fever. Two-hundred-fifty-five children underwent lumbar puncture. In 7 cases the CSF findings showed a bacterial meningitis, in 14 cases a viral meningitis. In 598 of the 623 children who did not undergo LP, a bacterial meningitis could be excluded on the basis of the clinical course. The data show that the probability of finding a bacterial or viral meningitis is high in children under 6 months of age even if no significant neurological signs are found on examination performed shortly after the seizure. In our study, older children affected by bacterial meningitis were clinically identifiable. In children aged 6 months to 3 years without important neurological signs, a complex seizure has been found to be a significant discriminating factor between patients with and without viral meningitis.