Background: With the widespread use of abdominal imaging, an incidentally found dilated common bile duct (CBD) is a common radiographic finding. The significance of a dilated CBD as a predictor of underlying disease and long-term outcome have not been well elucidated. Goals: A systematic review of studies on patients with dilated CBD was performed to identify etiologies and clinical factors that may predict which patients require further diagnostic testing and longterm outcomes. A PubMed search for relevant articles published between 2001 and 2014 was performed. Results: The search yielded a total of 882 articles, and after careful individual review for eligibility and relevancy, 9 peer-reviewed studies were included. A cause of the CBD dilation was found on average in 33% of cases and the most common causes were: CBD stone, chronic pancreatitis, and periampullary diverticulum. The overall CBD diameter was not associated with finding a causative lesion. Coexisting CBD and intrahepatic bile duct dilation, age, and jaundice were found to be indicators of pathologic lesions. Dilation of both the CBD and pancreatic duct was suggestive of pancreatic disease, especially pancreatic malignancy in the setting of obstructive jaundice. Follow-up was reported in 6 studies ranging from 6 to 85 months, and generally there was no change in the diagnosis. Conclusions: Incidentally found biliary tract dilatation can be a manifestation of significant biliary tract disease including malignancy. Long-term outcome is not well defined and further prospective studies examining the most cost-effective approach to evaluation are needed.