Safety of electroconvulsive therapy (ECT) in depressive patients with multiple sclerosis (MS) is still discussed and based solely on case reports. This kind of therapy was used in both unipolar depression and depression in bipolar disorder. It was suggested that ECT might cause the deterioration of neurological state (new MS lesions in magnetic resonance imaging). Moreover, there were also data indicating some anesthesiological complications and difficulties in patients with MS. We have presented a case of a patient who was treated with ECT and developed grand mal seizure after 14th electroconvulsive treatment.