The association of autoimmune antibody and HLA antibody has been documented concerning the pathogenesis of moyamoya disease. In this paper, we study the autoimmune antibody in moyamoya disease and discuss its relationship with the pathogenesis. Autoimmune antibody was evaluated in 13 cases of moyamoya disease. The age distribution of the patients ranged from 13 to 55, with an average of 37 years. Eight were females, 5 males. Autoantibody was studied with native DNA (double strand DNA) and ANA (antinuclear antibody). Antibody was noted in 3 cases (23%) in native DNA study, and 2 cases (15%) in ANA study. Significantly high incidence was recognized compared with normal control (4%). In relation to the clinical features, such as initial symptoms, time of onset, neurological findings, no significant correlation was recognized. This study suggests that immunological factors might play a partial role in the pathogenesis of moyamoya disease.