Infectious mononucleosis is a relatively common disease. In this paper, three patients with neurological symptoms related to infectious mononucleosis are described. Patient no. 1 had myelitis, one of the most frequent neurological complications. Patient no. 2 had cerebellar symptoms, with ataxia and disturbance of gait. In this case magnetic resonance revealed vermis atrophy, a finding which, to the best of our knowledge, has not been reported before. Patient no. 3 had bilateral optic neuritis. Repeated serologic tests may be necessary to confirm the diagnosis. Infectious mononucleosis should be considered in younger patients with neurological symptoms of uncertain origin.