OBJECTIVES: Cerebral aneurysms are pathological dilatations of the cerebrovasculature that are prone to rupture. Risk of aneurysm rupture is determined by size, location and patient co-morbidies, and five-year cumulative rupture rates have been reported to be as high as 50% in giant aneurysms1. The current study was undertaken to assess the differences in overall hospital discharge costs, length of stay (LOS) and all-cause mortality rates between inpatients with ruptured vs. unruptured cerebral aneurysms. METHODS: All inpatient discharges were selected from the Premier Perspective™ Database that had a primary diagnosis code for a ruptured or unruptured aneurysm, AND a primary procedure code for treatment of the aneurysm between 1/1/2008 and 6/30/2010 (index hospitalization). Costs, LOS and mortality were compared between ruptured and unruptured aneurysm groups. To minimize differences in baseline characteristics between groups, propensity adjustment was performed for age, gender and severity of illness (based on the Patient Refined Diagnosis Related Groups).  RESULTS: A total of 2,977 ruptured and 3,836 unruptured aneurysm discharges met the inclusion criteria for the study. After 1:1 propensity matching, 1,163 patients in each group were included in the analysis for outcome comparisons. Mean total cost per discharge was significantly higher in the ruptured group ($51,118, s.d. $33,790) than the unruptured group ($33,585, s.d. $32,255). Mean LOS was also significantly higher in the ruptured group (13.6 days, s.d. 12.7) vs. the unruptured group (6.5 days, s.d. 11.2). The all-cause mortality rate was significantly higher in ruptured (7.7%) vs. unruptured (1.8%) cerebral aneurysms. CONCLUSIONS: Preventing rupture in patients with cerebral aneurysms would likely decrease burden to the health care system, and also improve survival rates for patients. 1International Study of Unruptured Intracranial Aneurysms Investigators. Unruptured Intracranial Aneurysms: Natural History, Clinical Outcome, and Risks of Surgical and Endovascular Treatment. The Lancet. July 12, 2003, Vol 362, pp 103-110.