The authors report on a series of 100 posterior circulation aneurysms managed by surgical and endovascular procedures. The series consisted of 41 elective admissions more than 14 days after SAH or for unruptured aneurysms and 59 acute admissions after subarachnoid haemorrhage (SAH). In this first interdisciplinary series after the introduction of electrolytically detachable coils, surgical clipping was maintained as treatment of choice in good grade patients while endovascular therapy was primarily offered for patients in poor clinical grade or if the aneurysm was judged difficult to be accessed surgically. A total of 70 patients underwent aneurysm elimination, 54 surgically and 16 by the endovascular route. In 30 patients the aneurysm was not treated, either because of persisting grade 5 WFNS after SAH or because the risk of treatment appeared excessive with some complex unruptured aneurysms. A complication leading to permanent morbidity or mortality occurred after 5 surgical and 1 endovascular procedure (8.6%). Regarding overall management results after acute SAH, 14 of the total of 59 patients admitted with acute SAH died, corresponding to a management mortality of 24%. Although the present series cannot provide statistically firm conclusions, the authors believe from the actual experience and the accumulating literature, that the principal complementary aspect of the two treatment modalities is aneurysm location. Size and shape do not appear to be a primary factor to favour one or the other modality. The hope that endovascular therapy improves the prognosis of poor grade patients with posterior circulation aneurysms probably has been overstated. The good results of endovascular treatment with small narrow-necked aneurysms on proximal arteries of the posterior circulation, as seen in the present series and as reported in the accumulating literature, suggest that in future surgical and endovascular treatment should be considered as alternatives in these special cases while in large and broad-necked aneurysms surgery should be considered first.