A 23-year-old Japanese man was admitted to our hospital because of dry cough and lacrimal gland swelling. Laboratory findings showed hypergammaglobulinemia (4859 mg/dl), hypocomplementemia (CH50 13 U/ml), and hyperamylasemia. CT revealed a marked swelling of the bilateral lacrimal glands, diffuse patchy infiltration in the bilateral lung fields, and enlargement of the whole pancreas. Gallium citrate scintigraphy showed abnormal accumulation in the bilateral lacrimal glands, submandibular glands, and both lung fields. Biopsy specimens from the salivary gland revealed dense lymphoplasmacytic infiltration and abundant IgG4-positive plasma cells. Furthermore, open lung biopsy showed a marked peribronchial lymphoplasmacytic and eosinophilic infiltration with IgG4-positive plasma cells. These findings fulfilled the criteria of Mikulicz's disease and autoimmune pancreatitis, and support the recently proposed concept of IgG4-related systemic disease.