Prediction of development of the multi-phase alternative for the course inherent to acute disseminated encephalomyelitis (ADEM) is of great clinical importance, as it enables timely determination of the treatment tactics as well as volume of respective therapeutic interventions. This work is aimed at ascertaining the prognostic factors that determine the risk of development of the multi-phase course in disseminated encephalomyelitis. We have examined 101 patients with the diagnosis ADEM, namely: 28 men and 73 women in the age from 17 up to 53 years (average value 31.7 ± 1.01 years). To ascertain the prognostic meaning of clinic-paraclinic indices corresponding to patients with ADEM, we estimated the cumulative part of absence of relapses in the group of patients by using the Kaplan-Meyer method with estimating the Fisher criterion and using the most important clinic-paraclinic data. Development of the multiphase course in ADEM is reliably related to the following prognostic signs: changes in the neurologic status of patients with ADEM, degree of disability in accord with the EDSS scale as well as sizes of demyelination focuses determined using MRT. Criteria for congenial prediction in disease development with delayed appearance of ADEM relapses in the form of the multi-phase course are as follows: domination of motor impairments over coordinative impairments in neurological status, slight degree (in EDSS scale) of disability and small sizes (up to 4 mm) of demyelination focuses (MRT data). Our analysis of the main clinic-paraclinic indices obtained using the Kaplan-Meyer method indicates reliability of results and enables us to find a number of important prognostic criteria for appearance of the multiphase course in ADEM.