Transverse myelitis is an inflammatory disorder characterized by spinal cord dysfunction. Infectious, autoimmune, postinfectious and postvaccination diseases are the most common recognized causes of transverse myelitis, but near 50% of the cases are finally assumed as idiopathic. Rubeolla, mumps, rabies and influenza vaccines were associated with many neurologic complications, such as Guillain Barré Syndrome, acute disseminated encephalomyelitis (ADEM) and transverse myelitis. As a prevention measure after the 2009 pandemia, in February 2010 a National Campaigne of Vaccination against the Influenza A (H1N1) was started in our country. We report a case of a woman who received a monovalent Influenza A (H1N1) vaccine and four days after, began with sensory symptoms that progressed to a clear defined sensory level. She reached the clinical criteria of transverse myelitis, according to the Transverse Myelitis Consortium Working Group. One month later, the patient remained clinically stable and the MRI showed an improvement of the image without corticosteroids treatment. We discuss diagnostic, prognostic and therapeutic aspects of this clinical entity.