Backgraund and Objective: Anti-Saccharomyces Cerevisiae Antibodies (ASCA) that are considered to reflect immune response against increased intestinal permeability due to mucosal damage are among the serological markers of Crohn’s Disease. Methods: This microbial seromarker was recently shown to be elevated in several autoimmune disorders such as celiac disease, autoimmune liver diseases, type 1 diabetes, and Graves’ disease. Despite that fact, ASCA seropositivity in Autoimmune Polyglandular Syndrome (APS) has never been reported before. Results: Herein, we present a 46-year-old woman who has uveitis, autoimmune thyroiditis, and primary ovarian failure. Conclusion: Based on the coexistence of these diseases, the patient was diagnosed with APS type III. Moreover, ASCA seropositivity was detected although she has no overt intestinal disease.