We describe three females patients (age 40, 62 and 63 y) with nephrotic syndrome due to membranous nephropathy complicated by Sjögren's syndrome(SS). The patients satisfied the criteria for SS, but not those for systemic lupus erythematosus(SLE). All of them developed nephrotic syndrome, and light immunofluorescence as well as electron microscopy of renal biopsy specimens revealed membranous nephropathy. Two were positive for the SS-A antibody, and the other was positive for the SS-B antibody. Two were complicated with primary biliary cirrhosis (PBC) and autoimmune thyroiditis, whereas the other was complicated with interstitial pneumonia, but not with either PBC or autoimmune thyroiditis. Prednisolone (PSL) with or without cyclophosphamide improved the nephrotic syndrome in two of the patients. In conclusion, some patients with SS might become complicated with nephrotic syndrome due to membranous nephropathy if another systemic autoimmune disease exists.