Three-dimensional CT angiography (3D-CTA) and digital subtraction angiography (DSA) were compared as means for imaging the skull base venous system. 3D-CTA and DSA were performed on 209 sides of 109 patients to visualize the superficial Sylvian vein (SSV), deep middle cerebral vein (DMCV), and basal vein of Rosenthal (BVR). 3D-CTA clearly visualized the SSV, especially when it coursed along the middle cranial fossa, and flowed into the transverse sinus. However, 3D-CTA could not confirm the point of flow into the sphenoparietal sinus (SPS), cavernous sinus (CS), or pterygoid plexus. 3D-CTA was superior to DSA for delineating the flow of the insular vein or DMCV into the SPS, CS or BVR. The flow of the DMCV passed through the uncal vein into the SPS or CS in more than 60% of the cases, but into the BVR in only a few cases. The flow of the BVR passed into great vein of Galen in about half of the cases, and into the CS through the DMCV in almost all the others. The 3D-CTA provided excellent delineation of veins and their stereoscopic anatomical relationships with the bone structure or the arteries and it must be useful for landmarking and kind of venous treatment during operation. 3D-CTA is potentially a powerful means for operative planning of the pterional and anterior temporal approaches.