Some factors, enfluencing multiple sclerosis development, have been studied. Connection of tire disease with living close to metallurgical plants has been confirmed, as well as with prevailing meat products in food and with craniocerebral trauma. For the first time association of multiple sclerosis with infectionous eye diseases has been revealed, as well us with soft tissue absesses, critical dental caries, with contact with birds and with age of a father (senior than 31 y.o.) at the moment of a patient birth. The factors, determining unfavourable course of MS are: craniocerebral trauma without loss of consciousness, contact with agricultural animals, prevailing meat products in nutrition of persons at the age of untill 15 y.o. and disease beginning with cerebellar symptomatology.