The recent development of three-dimensional computed tomography (3D-CT) angiography with multi detector row CT (MDCT) improves cerebral artery imaging due to faster scanning at thinner collimation over a large scanning volume. Aneurysm clipping was performed using only 3D-CT angiography created by MDCT with 16 detector arrays (16-MDCT angiography), in place of digital subtraction angiography (DSA) to evaluate the suitability of 16-MDCT angiography for preoperative examination before aneurysm clipping, and identify the essential points when making 3D images. Thirty-two patients with subarachnoid hemorrhage (SAH) identified by initial CT or with non-ruptured aneurysm were entered in this study. Twenty-six SAH patients underwent 3D-CT angiography, and aneurysms were treated by clipping (n = 25) or coil embolization (n = 4). One patient with no aneurysm depicted by 3D-CT angiography underwent conventional DSA twice subsequently. The sensitivity of 16-MDCT angiography to depict aneurysms in patients with SAH, and time between admission and entering the operating room were evaluated, and compared with those under the former protocol using DSA. The sensitivity of 16-MDCT angiography for aneurysm detection was 100%. Shapes of all aneurysms depicted by 3D-CT angiography were validated intra-operatively. The mean operation waiting time was 2.8 hours, with the shortest time being 1.5 hours. Re-bleeding occurred in one of the 20 patients. We conclude that shorter preoperative waiting time decreased the incidence of premature re-bleeding, resulting in better outcomes. We highly recommend that the surgeon sets the threshold value, and rotates the 3D image to establish better surgical orientation.