We report an extraordinary case in which the venous route for pulmonary artery catheterization was unusual. A 41 year-old woman with an end-stage liver disease underwent a living-donor liver transplantation. After induction of anesthesia, the pulmonary artery catheter was revealed to be advanced into the left brachiocephalic vein and then slipped into another vein that drains into the left brachiocephalic vein. In this case, we assumed that the catheter had most likely slipped into the left pericardiophrenic vein since the catheter follows the left heart border similarly to the route of this vein according to the chest X-ray. Patients with liver cirrhosis develop many collateral vessels and have enlarged veins due to portal hypertension, which makes this vascular route possible. We present this case for anesthesiologists to be aware of the possibilities of unusual venous route due to dilated collateral vessels especially in liver transplant patients.