Since widespread vaccination, invasive Haemophilus influenzae type b (Hib) has become a rare infection. We here report the case of a 9-year-old boy admitted with seizures associated with fever and impaired general condition. First examination showed comatose child, Glasgow score 9/15, fever 38.2, deep tendon reflexes without frank meningeal syndrome. Laboratory tests showed polymorphonuclear neutrophils (PNN) with CRP 45.8. Cerebrospinal fluid (CSF) analysis revealed a cloudy appearance, pleiocytosis (6760 white blood cell count/ mm3) with neutrophil predominance (PNN = 90%, lymphocytes = 10%). Direct examination showed polymorphic bacilli, soluble antigen of Haemophilus influenzae type b, decreased glycorachy 0.04 mmol/L and hyper proteinorachie 4.097 g/L. MRI of the cerebellomedullary fissure revealed subtentorial and supratentorial encephalitis with bilateral parieto-occipital and cerebellar cortical and subcortical signal anomalies. The patient was treated with cefotaxime with favorable outcome. The patient had not been vaccinated against Hib in early childhood. After a 3-year follow-up, the patient was asymptomatic with no neurosensory sequelae. In subjects with severe Hib infection proof of vaccination or testing for underlying immunodeficiency are required.