A 44-year-old male was admitted because of nausea and fatigue. At admission, renal insufficiency was disclosed (serum BUN 94 mg/dL, Cr 8.4 mg/ dL). Serum protein electrophoresis was normal. Urine electrophoresis showed non-selective proteinuria with M component in gamma globulin fraction. Serum immunoelectrophoresis disclosed a predominance of free lambda chain protein. Bone marrow aspiration showed a heavy infiltration of immature plasma cells. Percutaneous renal biopsy showed 9 of 10 glomeruli were slightly increased in size. Cellularity and area of mesangium were also increased. Immunohistochemical staining of kappa and lambda light chain was negative. Electron microscopy showed sparse electron dense deposits with no deposition of amyloid-like fibrils in mesangial area. In summary, these finding were compatible with those of mesangial proliferative glomerulonephritis with acute renal failure associated with multiple myeloma (lambda light chain type). There was no published report like this case. Although serum creatinine decreased to 2.1 mg/dL following steroid-pulse therapy, renal function came to deteriorate again after a month of discharge. Permanent hemodialysis was applied.