Long-term natural history of unruptured cerebral aneurysms is not found frequently. Hence, the indications for surgery on unruptured asymptomatic cerebral aneurysms are still unclear. The benefit of treatment ultimately depends on the relative risk of subsequent aneurysm rupture in untreated patients versus the risk involved in surgery. Clinical features of fourteen elderly patients aged over 70 years with incidentally discovered unruptured aneurysms were analyzed. Two were male and 12 were female, with ages ranging from 70 to 82 years (mean: 74.5 years). Aneurysms were located in the anterior circulation in 13 patients and in the posterior circulation in 1 patient. One patient had multiple aneurysms, that is, bilateral middle cerebral aneurysms. The size of all these aneurysms was less than 10 mm. The indication for surgery was determined case by case. General information about the natural history of incidentally discovered aneurysms was given to the patients and their relatives. Informed consent was based on the fact that subarachnoid hemorrhage was associated with a poor prognosis, while excellent operative results were common in patients with unruptured aneurysms. Five patients agreed to surgical treatment. Four of them, their ages being 70, 70, 72 and 72 years old, with aneurysms located on the middle cerebral arteries, underwent neck clipping of their aneurysms with no operative morbidity or mortality. However, the remaining one patient was not recommended for surgery in spite of her consent to having it, because of her high age (82 years) and the location of her aneurysm (intracavernous internal carotid artery). Consequently, 10 patients who didn't receive surgery were followed-up at periods ranging from 3 months to 7 years. Two patients developed rupture of the aneurysms, either proven (one patient) or presumed (one patient). The former patient made an uneventful recovery after surgery, but the latter died. None of the remaining eight patients have experienced rupture of the aneurysms. It is our clinical impression, however, that they harbor an unruptured aneurysm with at least mild trepidation. With the rapid aging of the population, withholding aneurysm surgery merely because a patient is elderly may not necessarily be the most appropriate decision. Our conclusions are as follows: (1) Elderly patients in their early seventies are apt to agree to having surgical treatment for their unruptured aneurysms. (2) The cases reported herein show that asymptomatic middle cerebral artery aneurysms were able to be clipped very safely. (3) Most patients have experienced a decrease in quality of life from knowing they are living with an unruptured aneurysm.