OBJECTIVES: National and international guidelines are very heterogeneous about the necessity to perform a lumbar puncture (LP) in children under 12 months of age with a first simple febrile seizure. We estimated the risk of bacterial meningitis in children aged 6 to 11 months with a first simple febrile seizure. METHODS: This multicenter retrospective study was conducted in seven pediatric emergency departments (EDs) in the region of Paris, France. Visits of patients aged 6 to 11 months for a first simple febrile seizure from January 2007 to December 2011 were analyzed. Bacterial meningitis was sequentially sought for by 1) analyzing bacteriologic data at the time of the visit, 2) looking for data from a second visit to the hospital after the index visit, and 3) phone calling the child's parents to determine the symptom evolution after the index visit. Infants lost to this follow-up were searched for in a national bacterial meningitis database. RESULTS: From a total of 1,183,487 visits in the seven pediatric EDs, 116,503 were for children 6 to 11 months of age. From these, 205 visits were for a first simple febrile seizure. An LP was performed in 61 patients (29.8%). The outcome bacterial meningitis was ascertainable for 168 (82%) visits. No bacterial meningitis was found among these patients (95% confidence interval = 0% to 2.2%). None of the 37 infants lost to our follow-up were registered in the national database as having bacterial meningitis. CONCLUSIONS: Among children between 6 and 11 months of age with a first simple febrile seizure, the risk of bacterial meningitis is extremely low. These results should encourage national and international societies to either develop or endorse guidelines limiting routine LP in these infants and contribute to widely homogenized management practices.