Castleman's disease is a localized nodal hyperplasia in mediastinum or cervical area. It has been divided into 2 histologic types: hyaline-vascular type and plasma cell type. The hyaline-vascular type is more frequent, and characterized by small hyaline-vascular follicles and interfollicular capillary proliferation. The plasma cell type is characterized by the large follicles with intervening sheets of plasma cells. Systemic manifestation, such as fever, anemia, and hyperglobulinemia, are frequently associated with the plasma cell type. All the lesions are benign in behavior and the complete surgical excision is curative. Recently the authors experienced a case of Castleman's disease in the neck. The solid mass was removed completely and confirmed to Castleman's disease microscopically.