Mycotic aneurysms must be diagnosed rapidly because of the high mortality, associated with them. X-ray computed tomography (X-CT) is a noninvasive modality. Intravenous digital subtraction angiography (IVDSA) is also much less invasive and less dangerous than arteriography, especially in mycotic aneurysms, whose wall is thin. We describe two patients with mycotic aneurysms diagnosed by X-CT and IVDSA.