Purpose: Our goal was to describe the CT findings of aberrant left gastric vein (ALGV) and to evaluate the clinical significance of this vein. Method: Four patients in whom ALGVs were demonstrated by helical CT were examined. Each patient had either intrahepatic cholangiocarcinoma, cirrhosis with gastric varices, chronic hepatitis, or nonspecific abdominal pain. All patients underwent two phase helical CT, and the patient with cholangiocarcinoma underwent CT during arterial portography, and 3D images of the abdominal veins were obtained. Results: In all patients, the ALGVs ran along the hepatogastric ligament and were directly connected with the left portal branch. In the patient with cholangiocarcinoma, the portal vein had severe stenosis by tumor invasion, and both the ALGV and the aberrant right gastric vein functioned as a collateral pathway of the portal flow into the liver. In the patient with cirrhosis. dilated ALGV with hepatofugal flow caused gastric varices. Conclusion: The ALGV is directly connected with the left portal branch and may play an important role in the collateral pathway of the portal system.