With high resolution computed tomography (CT) of the skull, performing rapid series of 1.5 mm slices during an intravenous bolus injection of contrast medium, an angiography-like image (angio-CT) of the basal cerebral arteries can be obtained. From 76 consecutive angiographically or autopsy-verified cerebral aneurysms of various size down to 3 mm in diameter, 74 (97.4%) were shown up by the angio-CT. One ruptured and one incidental aneurysm escaped CT visualization. Besides the correct localization of the aneurysms, angio-CT provides information concerning the size and main direction of the aneurysms and yields, in addition, a coronal view of the aneurysms and their surrounding structures. Pitfalls for mis-diagnosis can be the following: Aneurysms of below 5 mm in diameter, located at the supraclinoid part of the carotid artery, multiple or non-ruptured aneurysms, bony or movement artefacts, poorly contrasted vessels due to wrong injection technique of contrast medium or vasospasm, and incorrect interpretation.