Résumé : Relapses of herpes simplex encephalitis (HSE) occurring after the completion of antiviral treatment have been reported repeatedly in children. The authors report data on six children who had at least one relapse of HSE. Two different mechanisms may account for these relapses, including viral replication or an immuno-inflammatory process, with different therapeutic attitudes. Relapses with viral replication may reveal host susceptibility to herpes simplex virus infection.