OBJECTIVES: To evaluate the diagnostic accuracy of three-dimensional digital subtraction angiography in the surgical or interventional treatment of intracranial aneurysms. MATERIAL AND METHODS: We reviewed the clinical records, radiological findings, and surgical results of seventy-two patients with eight-five aneurysms who had undergone 2-dimensional digital subtraction angiography (2-D DSA) and 3-D DSA as the diagnostic evaluation. 3-D images were compared with 2-D images and surgical or interventional results. The shape of the aneurysms, their necks, and their relationships to the parent vessels and other branches were evaluated. RESULTS: The existence of the aneurysms was diagnosed exclusively by 3-D DSA in 13 patients. The site (n=27) and the shape (n=15) of the aneurysms were evaluated more accurately with 3-D DSA than with 2-D DSA images. Depiction of aneurysmal necks and their relationships to the parent vessels was clearer with 3-D DSA images than with 2-D DSA images, especially in cases of the distal internal carotid artery aneurysms. CONCLUSION: With its advantages, such as unlimited projection, similarity to surgical view, and high resolution especially in the cavernous portion of ICA, the 3-D DSA provides more valuable information in the planning the surgical or interventional treatments of cerebral aneurysms.