Background. Multiple sclerosis (MS) is a central nervous system disorder characterized by inflammation, demyelination and neurodegeneration, and is the most common cause of acquired nontraumatic neurological disability in young adults. The course of the disease varies between individuals: some patients accumulate minimal disability over their lives, whereas others experience a rapidly disabling disease course. A part of patients with multiple sclerosis presents also seizures that lead to epilepsy. Several clinical series reported an association between multiple sclerosis and epilepsy. The most studies show an increased comorbidity between multiple sclerosis and epilepsy. The cumulative incidence of epilepsy by 10 years after diagnosis of MS was 1.9%. The probable anatomic basis for the seizures is areas of inflammation, edema, and/or demyelination in the cerebral cortex and the juxtacortical white matter generated by a mechanism that is not completely understood; the fact that these plaques are very common suggests that other factors must operate in view of the rarity of seizures in MS. In most cases, however, the prognosis of epilepsy was good and there seemed not to be any clear correlation between the severity of MS and epilepsy. Case report. A patient V. male, 41 years , came at a neurologist in April 2019 with the following complaints: facial hyperemia, heat sensations, alterations of consciousness with convulsive components in the anamnesis. At the same time: walking instability, recurrent diplopia, frequent urination, sleeping disorders, memory loss and decrease in body mass. Anamnesis: In 2005 patient has an acute respiratory infection, possible a flu. After a half a year had appeared diplopia, diplopia and frequent urination. In 2007 the diagnosis of multiple sclerosis was established. The diagnosis was confirmed in Moscow and the patient started the treatment with Galatimer acetate (Copaxone) that he administered for 5 years with the improvement of the evolution of the disease. Subsequently administered Acsoglatiran till present but without any obvious effect. In 2015 the patient has a seizure for the first time with unconsciousness but without warning signs. Other signs and symptoms associated with unconsciousness the patient doesn’t remember. A similar episode was in 2017. In 2019 the patient received symptomatic treatment in the neurology department for diagnosis: Multiple sclerosis clinically and imagistic defined, recurrent remissive form, in exacerbation, with pronounced atactic syndrome. Structural epilepsy-mesial temporal sclerosis on the right associated to multiple sclerosis plague with focal seizures with bilateral passage treated with Carbamazepine retard 300 mg/day. Now the antiepileptic treatment is Timonil 750 mg/day with a very good outcome. Conclusions. MS is a risk factor for developing epilepsy. Patients with MS have a threefold increase in risk for developing epilepsy when compared with that expected in the general population. The reason for this increased risk is unclear and needs further investigation.