A prospective analysis of 80 consecutive operated cases of aneurysm were carried out to know the prognostic factors in intracranial aneurysmal surgery. Analysis of end-results with respect to aneurysmal locations and timing of operation showed that the internal carotid artery aneurysm did not make difference in outcome regardless of the timing of surgical intervention, but anterior cerebral artery, middle cerebral artery, and multiple aneurysm were more poor outcomes in the early surgical group(p<0.05). The more grave initial neurological state showed the worse surgical end-results. The poor results were shown in cases of above 3 mm in thickness of the basal cisternal hemorrhage and/or above 30 ml in volume of the intracerebral hematoma on the brain CT scan. During the operation, no sunkened brain, a spasm of offending artery, premature rupture of aneurysm, and post-operative residual intracerebral hematoma were also adverse effects to the post-operative outcomes.