Renal vein thrombosis (RVT) was diagnosed in 12 of 60 patients with nephrotic syndrome with CT scan and confirmed by selective renal angiography. Of the 60 patients, 50 had primary glomerulonephritis with various pathological findings and 10 lupus nephritis. CT is valuable in screening renal vein thrombosis. Renal vein and cubital vein blood in the 12 patients were drawn for assay of FDP, AT III, VIIIR: AG, fibrinogen; the results indicated the presence of a state of hypercoagulation. Of these, 7 were given 200,000 units of urokinase (UK) in divided doses into renal vein within one hour and 5,200,000 units UK into renal artery in the same way. Patients also received 2.5mg/d warfarin and 75mg/d persantine. Except for the 3 with focal sclerosis, patients received 40mg/d prednisone. After 1 month CT and blood fibrinogen, FDP, AT III, VIIIR: AG studies were repeated. RVT in patients with intraarterial UK had complete dissolution of their thrombi. Complete dissolution occurred in 2 of the 7 receiving UK by renal vein and there was partial dissolution in the other 5. It seems that intraarterial injection yielded better results. Hypercoagulation state was alleviated in all patients with UK therapy.