The purpose of this study is to evaluate the utility of three-dimensional computed tomographic angiography (3D-CTA) as the primary diagnostic investigation in patients with spontaneous subarachnoid haemorrhage (SAH) from anterior circulation aneurysms, and to correlate the results with digital subtraction angiography (DSA) and intraoperative findings. From May 2005 to May 2007 a total of 38 consecutive patients admitted for SAH, suspicious for ruptured anterior circulation cerebral aneurysm, underwent 3D-CTA. Inclusion criteria were a SAH confirmed by a non-contrast head computed tomographic scan or by lumbar puncture. Exclusion criteria were: previous DSA, severe contrast medium allergy and severe renal failure. All patients underwent early surgical clipping of the aneurysm. The mean time between SAH onset and surgery was 43.6 h (range, 14-74 h). The 3D-CTA was performed in all cases; and in 13 out of 38 patients (34%) represented the only preoperative exam. In all patients that underwent surgery with the sole 3D-CTA, the images collected allowed a good visualisation of the morphology of aneurysms and of the anatomical relationship with the vascular structures. 3D-CTA allows accurate diagnosis with an excellent visualisation of ruptured aneurysms of the anterior circulation. Our results suggest that, in selected cases, ruptured anterior circulation aneurysms could be successfully treated on the basis of 3D-CTA alone.