Castleman's disease is a heterogeneous group of lymphoproliferative disorders with unknown etiology presenting with lymphadenopathy. Although Castleman's Disease may occur anywhere along the lymphatic chain, the mediastinum is the most common location (70%). We represent 36-year-old male patient with homogeneous retroperitoneal mass that interrelated with renal hilum of the right kidney in abdominal tomography. Surgical complete resection performed and histopathological diagnosis of the resected tissue was hyaline-vascular type of Castleman's disease It is histologically and prognostically distinct from malignant lymph-node hyperplasia. Although Castleman's disease is rare condition, it should always be kept in mind in the differential diagnosis of retroperitoneal tumors.