Renal complications of Castleman's disease are uncommon. Among the various renal disorders, including mesangial proliferative glomerulonephritis, membranous glomerulonephritis, and minimal change disease, nephrotic syndrome attributable to renal amyloidosis is very rarely reported. We report a case of mixed type of localized Castleman's disease complicated with nephrotic syndrome. Renal biopsy was performed. The deposition of AA amyloidosis was shown. After the removal of two mesenteric lymphoid masses, the proteinuria was gradually decreased and disappeared. Renal biopsy was repeated after 14 months, and, despite complete remission of nephrotic syndrome, no regression in amyloid deposition was found.