We report a 25-year-old man who presented with congenital absence of the portal vein, or Abernethy malformation, a rare congenital disorder in which the mesenteric and splenic venous drainages bypass the liver and directly drain into the inferior vena cava through an extrahepatic portosystemic shunt. Magnetic resonance imaging, which showed multiple nodular lesions in both liver lobes that were associated with an absence of intrahepatic portal venous branches, strongly suggested the diagnosis of the Abernethy malformation. Carbon dioxide wedged venography and transvenous liver biopsy, which were performed in the same session by a right jugular approach, confirmed these findings. This technique can be considered a valuable alternative diagnostic tool to catheter arteriography and percutaneous transhepatic liver biopsy.