To retrospectively assess the value of multiplanar reformations (MPRs) compared with standard axial images in the assessment of hilar and extrahepatic bile duct cancer. Forty-eight patients with confirmed bile duct cancer were included as preoperative work-ups; all of these patients underwent contrast-enhanced multidetector CT consisting of axial and MPR images. Two radiologists independently assessed the axial images alone and the combined axial and MPR images in the coronal and sagittal planes for the presence of tumor, its extent, vascular involvement, and resectability. The results were compared with surgical and pathologic findings. For tumor presence and conspicuity, combined axial and MPR images had higher values than the axial only images. For evaluation of tumoral extent, there was no difference between the two image sets for either reader. The accuracy for tumor extent was lower in hilar cancer than in extrahepatic bile duct cancer. For evaluation of vascular involvement and resectability, the area under the receiver operating characteristic curve of axial images was not significantly different from that of the reformatted images. The addition of MPR images to the standard axial images did not significantly improve the diagnostic performance of MDCT in the evaluation of the bile duct cancer.