Idiopathic plasmacytic lymphadenopathy (IPL) with polyclonal hypergammaglobulinemia has been proposed as a new disease entity resembling the plasma cell type of multicentric Castleman's disease. Here, we report a case of IPL accompanied by renal failure and skin involvement. A 35-year-old man was admitted for advanced renal failure, anemia, systemic lymphadenopathy and skin rashes. Laboratory examinations indicated polyclonal hypergammaglobulinemia and elevated serum interleukin-6 (IL-6). Biopsy of a cervical lymph node revealed follicular hyperplasia with normal germinal centers, sheets of polyclonal proliferating plasma cells and the absence of marked proliferation of blood vessels in the interfollicular area. Lesions of the kidney and skin also had pathological characteristics of IPL. Following a diagnosis of IPL, corticosteroid therapy successfully improved the anemia and hypergammaglobulinemia, and serum IL-6 levels decreased to a normal range. This case may give suggestions about diagnosing and preventing the progression of complications from this disease entity.