Two hundred and twenty-two duplex ultrasonographic examinations were performed on 36 liver transplants in 30 patients over a period of 5 years and 9 months. Positive sonographic findings were correlated with 13 angiographic examinations. Arterial complications included 4 thromboses, 5 stenoses, and one mycotic aneurysm. A false-negative result was obtained in 2 cases of stenosis and a false-positive result in one case of thrombosis. One portal vein thrombosis, 2 stenoses, and 2 cases of portal hypertension were diagnosed correctly. Sensitivity was 87%, specificity 95%, and accuracy 93%. Duplex Doppler was least effective in the diagnosis of hepatic artery stenosis. Five cases showed biliary complications of ischemic origin. Angiography is indicated when duplex Doppler is positive or doubtful, but also when the clinical condition is unclear.