Renal complications in Waldenström's macroglobulinemia (WM) are infrequent and are characterized by the presence of PAS positive amorphous hyaline deposits in the capillary lumen, infiltrated with lymphoplasmatic cells with PAS positive inclusions in the interstices and intratubular hyaline cylinders. Membranous glomerulonephritis may be a paraneoplastic manifestation of the lymphoproliferative processes. A 67-year-old male was diagnosed of WM, type-I cryoglobulinemia with renal insufficiency without proteinuria. Renal histological examination revealed changes characteristic of nephropathy associated to WM as well as membranous glomerulonephritis. This association has not been described previously. The coexistence of two pathogenic mechanisms with a common base, lymphoproliferative disease, may explain this association.