Antibodies directed against glial cells may be involved in autoimmunity in multiple sclerosis (MS). Using a tissue culture system, the presence of glial cell antibodies in MS-patient serum was detected through immunofluorescent technique. Thirty one of 73 MS-sera were strongly positive for anti-glial cells, 13 were equivocal and 29 were negative. The antibody staining was either cytoplasmic or associated with cell surface membrane, and involved IgG type of antibody.