Glomerular lesions have been reported to occur in association with a wide variety of malignancies, particularly carcinomas and lymphomas. Patients with the neoplastic diseases are exposed to continuous antigenemia, which stimulates antibody production and forms circulating immune complexes. Membranous nephropathy appears to be the most common glomerular lesion in patients with solid tumors, and minimal change glomerulopathy is another major form of glomerular disease associated with lymphomas, particularly with Hodgkin's disease. Three cases of nephropathy associated with anaplastic oat cell bronchial carcinoma, gastric adenocarcinoma and Hodgkin's disease were studied histologically, ultrastructurally and by immunofluorescence. The diagnosis of glomerulopathy preceded the diagnosis of malignant disease. All three patients were admitted to hospital because of nephrotic syndrome. The paraneoplastic glomerulopathies were histologically identical to that of idiopathic membranous glomerulonephritis and minimal change glomerulonephritis. Adult patients over the age of 50-60 with nephrotic syndrome caused by glomerulonephritis, especially by membranous nephropathy, should be screened for cancer.