BACKGROUND The optimal time to operate on an intracranial aneurysm eludes a satisfactory answer. While most surgeons would agree to operate early in young and neurologically intact patients, the ideal timing in older and neurologically impaired patients is debatable. In India, the majority of centers operate on patients in Hunt and Hess grades I-III, but is circumspect about grades IV and V. PURPOSE The following study was carried out to check the effect of vasospasm on mortality rates and time of surgery being performed on the patient after having the same in patients coming under criteria of Hunt and Hess grades IV and V. METHODS We undertook a prospective evaluation of 171 consecutive patients of aneurysms operated during the last 9 years irrespective of their age, neurological grade, and time of presentation or vasospasm in an attempt to resolve this issue. The influence of vasospasm on each neurological grade was examined. RESULTS It appears that concomitant presence of vasospasm in grade III, IV and V patients indicates a possible "reversible" cause of the poor neurological status, while its absence may indicate an irreversible or more extensive primary insult. CONCLUSION The presence of vasospasm in poor grade patients appears to be a better prognostic indicator.