A retrospective analysis was performed on all aneurysms operated on by one of us (SLG) from July 1980 to October 1988 to determine the factors that govern outcome from the intraoperative rupture of aneurysms. A total of 276 consecutive surgical procedures for 317 intracranial aneurysms produced 41 perioperative or intraoperative ruptures for analysis. Five cases were pre-exposure ruptures, 3 of which occurred during anesthetic induction. Four of these patients died, and 1 made a good recovery. Of the remaining 36 cases, outcome was analyzed in terms of the adjuncts used to deal with the intraoperative rupture. There was no statistically significant difference in outcome between those cases in which tamponade was used to control hemorrhage versus temporary clipping; however, those cases in which hypotension was used did less well than those in which it was not used. From October 1986 to October 1988, 108 operations for 132 aneurysms were performed without the use of induced hypotension. There were 16 intraoperative ruptures (14.8%). All 16 of these patients made a good recovery. In the group before 1986, of which there were 20 intraoperative ruptures (of 168 operations, 11.9%), 11 of those 20 patients suffered a permanent deficit or died. We conclude that hypotension may not be a necessary adjunct to the management of intraoperative rupture of aneurysms.