The non-osmotic stimulation of arginine vasopressin release from the pituitary gland has been implicated as one of the important factors in abnormal water retention in patients with NS.We present the initial description of a patient with massive edema caused by refractory nephrotic syndrome, which was effectively treated with tolvaptan, a selective oral vasopressin V2 receptor antagonist.Tolvaptan is effective for the treatment of massive edema caused by NS