Immunoglobulin G4-related disease (IgG4-RD) is a systemic disease, and lymphadenopathy is frequently observed in these patients. Among the 5 subtypes of IgG4-related lymphadenopathy, progressively transformed germinal centers (PTGC)-type IgG4-related lymphadenopathy possesses a unique characteristic that differentiates it from the other 4 subtypes. Here, we report on a rare case of PTGC-type IgG4-related lymphadenopathy accompanying Mikulicz's disease. A 39-year-old female complained of a left cervical mass and bilateral upper eyelid hypertrophy. The serum level of IgG4 was elevated, and computed tomography showed enlargement of the bilateral lacrimal and submandibular glands and left cervical lymph node. Excisional biopsy of a submandibular gland and cervical lymph node was performed, and the histopathologic findings revealed Mikulicz's disease accompanied by PTGC-type IgG4-related lymphadenopathy. After treatment of the patient with oral prednisolone and azathioprine, the patient's appearance improved. To the best of our knowledge, no case of PTGC-type IgG4-related lymphadenopathy has been previously reported in Korea.