Biliary cystadenomas are rare biliary ductal neoplasms of congenital origin. There is an excellent correlation between CT and sonographic findings for number, size and location of the lesions. However, sonography can demonstrate better morphologic features such as thickened wall, mural nodules and septations. CT shows more clearly the accurate size and location of the neoplasm to surrounding structures. Angiography is not diagnostic; however, it can help to distinguish between benign and malignant lesions. MRI provides useful information for surgical planning, demonstrating well the relationship of the tumor to vascular structures and other organ systems. Complete excision is the treatment of choice to prevent recurrence or malignant transformation of biliary cystadenomas.