A 71-year-old male with a past history of lower limb arteriosclerosis obliterans developed nephrotic syndrome and renal dysfunction. Renal biopsy showed diffuse global endocapillary proliferative lesions with infiltration of mononuclear cells and occasional foam cells. An irregular double contour of the glomerular basement membrane and global mild-to-moderate mesangial proliferative lesions were observed, indicating membranoproliferative glomerulonephritis. Congo red staining was negative. Routine immunofluorescence studies showed no obvious immunoglobulin or complement depositions. Electron microscopy showed endocapillary proliferative lesions and infiltration of macrophages with abundant lysosomes. Irregular subepithelial, subendothelial, and mesangial electron-dense deposits were observed in glomeruli. In these electron-dense deposits, parallel arrangement striated structures were detected. All known disease entities with Congo red-negative and immunoglobulin-negative glomerular deposits were pathologically excluded. The glomerular lesion in our case might be a new disease entity. .