Acute disseminated encephalomyelitis (ADEM) is a monophasic demyelinating disease that usually follows an infection or vaccination, mainly by the measles virus and occurring primarily in children and young adults. His association with infection by hepatitis A virus is rare, and is poorly documented. The case of a 53 years old female patient with ADEM and infection by hepatitis A is presented. The inclusion of hepatitis A within the causal screening of adult patients with ADEM is highlighted. (Acta Med Colomb 2014; 39: 64-68).