The authors report two cases of transverse myelitis due to Mycoplasma pneumoniae occurring during a recent acute infection due to Epstein-Barr virus (EBV). The clinical picture included weakness of the legs, bladder dysfunction, fever, headache and in one case, a mild confusional state. Magnetic Resonance Imaging (MRI) revealed a segmental edema of the lumbar tract and cerebro-spinal fluid analysis showed a mild pleocytosis and an increased level of proteins with a blood-brain barrier damage. The diagnosis of acute infection due to Mycoplasma pneumoniae was made on serological criteria. The patients recovered completely after a 14-day course of an associated regimen with Ciprofloxacin (400 mg/day i.v.) plus prednisone (60 mg/day i.v.). The authors emphasise the immunological disorders in the combined infection with Mycoplasma pneumoniae and EBV, supposing that an infective mononucleosis may predispose to mycoplasmic transverse myelitis.