The urgency of the problem of acute encephalitis and meningoencephalitis in children is determined by the severity of the course, a high probability of adverse outcomes such as disability and neurological consequences, as well as significant mortality among children who become ill.An in-depth examination of these patients is carried out by neurologists and infectious disease specialists, but every practicing pediatrician should suspect this pathology in children. As is often the case in infectious diseases, timely diagnosis and referral to specialized infectious or neurological departments contribute to the appointment of timely and adequate therapy and can even cope with severe forms of encephalitis, minimizing the effects of past diseases. If 30 years ago it was only possible to ascertain the etiology of encephalitis, then at present there are effective antiviral drugs for the etiotropic treatment of this group of patients. New possibilities of diagnosing encephalitis using serological and instrumental methods of examination, which are increasingly being introduced into clinical practice, have been developed.Special emphasis in the educational-methodical manual is made on the clinical and diagnostic aspects of encephalitis of various etiologies.