Magnetic resonance and computed tomographic angiography have been increasingly applied to the study of disease affecting the cerebral vasculature. Despite these advances, however, conventional cerebral angiography clearly remains the diagnostic gold standard and essential guide to any microneurosurgical or endovascular therapeutic decision concerning cerebral aneurysms. Detailed cerebral angiography is a dynamic study and is influenced by prior axial imaging. It should be tailored to the specific circumstance to obtain information required for selection of the most beneficial treatment.