Listeria monocytogenes infections can involve the central nervous system in the form of a rhomboencephalitis. Three possible cases of rhomboencephalitis by Listeria monocytogenes are reported (2 females, aged 44 and 49 and a man of 36 years old). The three cases were preceded by an unspecific prodrome of headache, vertigo and fever in absence of a meningeal syndrome. The neurological stage was defined by the unilateral involvement of cranial nerves and the cerebellum and a clear inflammatory cerebrospinal fluid (CSF) with the presence of polymorphonuclear leukocytes, and normal glucose and protein levels. A magnetic nuclear resonance (MRI) showed the appearance of characteristic images, present in the bulboprotuberancial region. These images are one of the most constant features of this disease, reported in the literature. The early diagnosis of rhomboencephalitis was based on the clinical picture, the study of the CSF and the MRI, allowing the use of antimicrobials, prior to microbiological identification. Therefore, the risk of brain stem and cardiac complications of the disease is reduced (Rev Méd Chile 2003; 131: 921-8)