The authors reported a case of a dural arteriovenous fistula (DAVF) in the left transverse-sigmoid sinus, in which 3-dimensional computed tomography (CT) angiograms (3D-CTAs) by a 64-section multidetector row CT scanner were useful for its diagnosis and treatment. The DAVF in the left transverse-sigmoid sinus appeared on the digital subtraction angiogram. 3D-CTAs were obtained by a 64-section multidetector row CT scanner before an endovascular treatment. The feeders and draining veins of the DAVF were clearly demonstrated on the 3D-CTAs, which clarified the relationship between the normal dural sinuses and DAVF. The DAVF was successfully treated with endovascular surgery, a transvenous embolization through the mastoid emissary vein, which was easily detected by using the 3D-CTA, showing both the subcutaneous vein and calvalium. 3D-CTAs by a 64-section multidetector row CT scanner are useful for both diagnosis and treatment of DAVFs.