: Both adult-onset growth hormone deficiency and autoimmune polyglandular syndrome are more frequent clinical entities than previously thought. In light of research carried out in recent years, it seems that growth hormone deficiency may be associated with proinflammatory state. This study describes a unique case of adult-onset growth hormone deficiency secondary to a traumatic brain injury in a young man, which was followed by the development of autoimmune polyglandular syndrome type 3. We discuss diagnostic and treatment dilemmas associated with discovering and management of both disorders in this patient. We conclude that in predisposed individuals growth hormone deficiency may lead to the development of autoimmune disorders of endocrine glands and/or exacerbate their clinical course.