Cognitive impairment has been recently recognized in patients with pediatric multiple sclerosis in more than 30% of cases. Altered functions with variable frequency are: attention, language (receptive, verbal fluency, naming), visual-spatial and motor functions, spatial memory, executive functions and abstract reasoning. Fatigue and affective disorders are associated, but not correlated with cognitive impairment. The frequency and severity of cognitive impairment increase with time. Cognitive impairment has a negative impact on patient's life limiting social, academic and recreational activities.