Bacterial meningitis is a particularly dangerous infection of the central nervous system involving quite a number of mortal cases and frequent neurological sequelae. Etiology varies in relation to the patient's age. In the first 2 months of life Streptococcus B, Listeria monocytogenes, Escherichia coli and other Gram negative enteric bacilli are more frequently isolated while in older children Haemophilus influenzae, Neisseria meningitidis and Streptococcus pneumoniae are more common. Clinical symptoms take a different form according to the patient's age: symptoms of a general kind prevail in the first 2 months of life while in older children signs of meningeal irritation predominate. In a review of the survey of cases of bacterial meningitis observed at the Clinica Pediatrica in Pisa from 1970 to July 1993, with a retrospective research, 208 patients have been examined, considering age, etiology, clinical course especially observing the course of temperature, liquor characteristics, normalisation of the index of phlogosis, mortality and neurological sequelae. In the last ten years the availability of 3rd generation cephalosporin has provided the possibility of comparing two groups of patients of an age ranging between 1 month and 14 years. Twenty cases were treated with ampicillin and chloramphenicol and 30 cases with cephalosporins the evaluation made considering the course of temperature, the normalization of the liquor index has revealed a more favourable clinical course in the second group of patients.