A series of nine patients with an unruptured asymptomatic aneurysm not associated with a ruptured aneurysm is discussed. Three had giant aneurysms. Two patients had bilateral aneurysms of the middle cerebral artery. Five had solitary aneurysms of the middle cerebral artery. One had an aneurysm of the anterior communicating artery. One had an ophthalmic aneurysm. All aneurysms were clipped. Two operations were necessary in the two patients with bilateral aneurysms. There was no mortality and no significant morbidity. Clipping of the aneurysm is recommended for those patients who have no other serious illness that significantly increases the surgical risk. If a combination of pituitary tumor and aneurysm is found, a subfrontal instead of transsphenoidal approach should be considered so as to treat both the tumor and aneurysm at the same operation.