Fifteen cases of renal vein thrombosis were seen in patients with nephrotic syndrome, both adult and pediatric, and all had kidney biopsies. Six patients were found to have membranoproliferative glomerulonephritis, 3 membranous nephropathy, 2 focal segmental glomerulosclerosis, 2 renal amyloidosis and one each minimal change disease and diffuse mesangial proliferative glomerulonephritis. The diagnosis of renal vein thrombosis was made in all patients by utilizing digital subtraction venography. This method is simple, safe, noninvasive and quite efficient.