The antibodies neutralizing Baikal seal morbillivirus (BSMV) were studied in sera from 148 normal Baikal seals (Phoca sibirica). The virus-neutralizing antibodies were demonstrated in sera of 61.5% of the animals examined. A comparative analysis of antibodies in NT and cell-ELISA method is presented. The role of BSMV in morbidity and mortality of seals (Phoca sibirica) is discussed.