Hydrocephalus is one of the major complications following spontaneous subarachnoid hemorrhage(SAH) as a result of intracranial aneurysm rupture. But the diagnosis and treatment of hydrocephalus is not often a straightforward task because of diagnostic uncertainties. From 1991 to 1995, twenty patients who developed hydrocephalus and received ventriculoperitoneal shunt operations(VP shunt) among total of one hundred ninetynine patients with ruptured intracerebral aneurysms were retrospectively studied. We investigated to obtain possible prognostic factors regarding to VP shunt operations among several parameters: such as age, sex, radiological findings, clinical findings, and their actual influence on the result of VP shunt operations. Of the twenty patients, thirteen patients(75%) showed clinical improvements after shunt operations. Cortical effacement on brain CT, gait disturbance, memory disturbance, and increased ventriculocranial volume ratio(>5%) were appeared to be significant prognostic factors for good results after VP shunt operations.