We report here four cases of systemic lupus erythematosus associated with the nephrotic syndrome and renal vein thrombosis and review six familiar cases previously noted in the literature. Renal biopsy in each of our cases showed changes consistent with the membranous type of lupus nephropathy. We discuss the exclusive appearance of this pattern in relation to renal vein thrombosis in other forms of renal disease. The occurance of renal vein thrombosis in patients with systemic lupus erythematosus and the nephrotic syndrome supports the evidence that the thrombosis is a complication rather than a cause of the nephrotic syndrome. The presence of pleuritic pain in a patient with systemic lupus erythematosus and the nephrotic syndrome should alert the clinician to the possibility of renal vein thrombosis and pulmonary emboli. With appropriate diagnosis and anticoagulation therapy, our patients had a benign course during 7 to 48 months of follow-up.