Auto-antibodies to different thyroid cell components in serum of patients with thyroid disease have been estimated. Some types of antibodies were detected only in sporadic cases of nonthyroid auto-immune diseases. This study was performed on 24 patients who had alopecia totalis. Although they had normal serum free T3, T4 and TSH levels, five patients had significantly increased anti-microsomal antibody and one patient had both increased antithyroglobulin and antimicrosomal antibody levels. These results suggested that in alopecia totalis cases, it is reasonable to analyse thyroid antibodies because they can be taken as one part of the abnormal immune reactivity.