A 70-year-old female complained of palpitation. CBC demonstated anemia and bone marrow aspiration smear demonstrated absence of erythroid hematopoietic cells, and pure red cell aplasia (PRCA) was diagnosed. Computed tomography (CT) demonstrated abdominal tumor. Biopsy of the abdominal tumor showed proliferation of lymph follicles with small and medium-sized lymphocytes, angiofollicular pattern in their center, and hyalinization around the surrounding tissue. Based on these findings, Castleman's disease (CD) of hyaline-vascular (HV) type was diagnosed. Since anemia progressed, a possible relation between the pathogenesis of PRCA and CD was considered. Therefore, prednisolone (PSL) was dministered for two months as well as two courses of COP (cyclophosphamide, oncovin and prednisolone) chemotherapy and 40Gy radiation to the abdominal tumor. After these treatments, the size of abdominal tumor decreased, but PRCA did not improve. Subsequently cyclosporine was administered for five months, and was effective for the improvement of anemia. These results indicated the immunological pathogenesis of PRCA even in Castleman's disease of hyaline-vascular type.