Immunoglobulin G4-related disease has become the focus of interest in recent years. The disease is characterized by inflammation of the organs involved, often with a macroscopic appearance suggestive of a tumor, elevated immuno-globulin G4 levels, immunoglobulin G4-positive plasma cell infiltration on histological examination, fibrosis, oblit-erative phlebitis, and typically a rapid therapeutic response to corticosteroids. The disease can show a variety of organ manifestations, with frequent involvement of exocrine glands. Among the endocrine organs, symptoms may appear in the thyroid gland and the pituitary gland. The criteria for immunoglobulin G4-related hypophysitis were formu-lated in 2011. Until a few years ago, a condition formerly known as Riedel's thyroiditis was identified as immuno-globulin G4-related thyroiditis. Based on the criteria system for immunoglobulin G4-related thyroid diseases pub-lished in 2021, some patients with Hashimoto's thyroiditis and Graves' disease can also be classified as immunoglobulin G4-related thyroid disease. The identification of immunoglobulin G4-related endocrine diseases and the establishment of an accurate diagnosis can modify the treatment of the patient and determine the course of the disease. Other organ manifestations should be sought in patients with immunoglobulin G4-related endocrine disease and lifelong immunological follow-up is warranted.