Mycoplasma pneumoniae (M.p.) is generally responsible of upper and lower respiratory tract infections in children in school age; in about 2% of cases can be also considered the cause of a NS infection: meningitis, encephalitis, cerebellitis, transverse myelitis and ascending polyradiculitis. The authors describe a case of meningitis following an acute otitis media in a 6 years old child. This patient presented also a fourfold or greater decrease in titer of complement fixing antibodies to M.p. The authors suggest a systematic research of M.p. in patients with clear CSF meningitis.