Aim:Surgical procedures for aneurysmal subarachnoid hemorrhage (SAH) are increasing among the elderly as the population ages. Chronic shunt-dependent hydrocephalus is a recognized complication of SAH. The purpose of this study was to identify factors predictive of the development of shunt-dependent hydrocephalus among elderly patients with SAH.Material and Methods:We retrospectively studied 878 patients, including 275 patients ≥ 65 years old, with SAH treated between 2005 and 2015 to identify factors contributing to the development of shunt-dependent hydrocephalus. The relationships between shunt-dependent hydrocephalus and the causative factors were analyzed using univariate and multivariate analysis; the causative factors studied were based on the results of previous studies.Results:In the 878 patients with SAH, there was a significant difference in the incidence of shunt-dependent hydrocephalus between patients < 65 years old and those ≥ 65 years old (p=0.021). In the 275 patients ≥ 65 years old, the following were associated with shunt-dependent hydrocephalus on univariate analysis: 1) Hunt and Hess grade (p=0.005), 2) Fisher grade (p<0.001), 3) intraventricular hemorrhage (p<0.001), 4) acute hydrocephalus (p=0.003), 5) aneurysm location (p=0.001), and 6) external ventricular drain placement (p<0.001). On multivariate analysis, only 1) intraventricular hemorrhage (p<0.001) and 2) a ruptured aneurysm located in the distal posterior circulation (p=0.014) were related to an increased risk for the development of shunt-dependent hydrocephalus.Conclusion:Evaluating risk factors can help identify patients at high risk of developing shunt-dependent hydrocephalus. Identifying these risk factors may help neurosurgeons provide optimal therapy and improve outcomes in patients with SAH.