Objective: To report an uncommon presentation of a rare case of autoimmune polyglandular syndrome type IIIb in a patient presenting as well with Small Duct Primary Sclerosing Cholangitis. Clinical Presentation and Intervention: A 42-year-old man presented with jaundice and intermittent fever. Blood tests showed macrocytic anaemia due to vitamin B 12 deficiency compatible with Biermer’s disease. A thyroid function test was consistent with hyperthyroidism compatible with Basedow’s disease. And Liver biopsy revealed signs compatible with Small Duct Sclerosing Cholangitis. A final diagnosis of Small Duct Sclerosing Cholangitis with Biermer’s disease and Basedow’s disease, which constituted autoimmune polyglandular syndrome type IIIb, was made and the patient was treated with L-thyroxine, vitamin B 12 injection and Ursodeoxycholic acid with a impressive improvement during his follow up. Conclusion: This case showed a rare combination between APS type IIIb and Small Duct Sclerosing Cholangitis and that the presence of one autoimmune endocrine disease should prompt clinicians to look for other coexisting autoimmune diseases which may be asymptomatic.