Background : Aneurysmal subarachnoid hemorrhage (aSAH) is a severe neurological event with limited treatment options, and little is known about its pathophysiology. There are few objective tools for predicting outcomes of aSAH patients and further aiding in directing clinical therapeutic programs. This study aimed to determine whether an elevated serum D-dimer/albumin ratio (DAR) reflects disease severity and predicts aSAH outcomes. Methods : We included 178 patients with aSAH. Data included demographics; clinical severity of aSAH (World Federation of Neurological Societies (WFNS) grade and Hunt-Hess grade); levels of D-dimer, albumin, and c-reactive protein (CRP); leukocyte counts on admission; and three-month outcomes. The outcomes were dichotomized into good and poor. The predictive ability of DAR for outcomes was determined using receiver operating characteristic (ROC) curve analysis. Results : Serum DAR showed a positive correlation with disease severity. Univariate analysis revealed that DAR, WFNS grade, Hunt-Hess grade, delayed cerebral infarction (DCI), age, neutrophil-to-lymphocyte ratio (NLR), and CRP/albumin ratio (CAR) were associated with unfavorable outcomes. Multivariate regression analysis further revealed that elevated DAR predicted poor outcomes after adjusting for WFNS grade, Hunt-Hess grade, DCI, age, NLR, and CRP/albumin ratio. Receiver operating characteristic curve analysis revealed that DAR predicted outcomes at a level comparable with NLR and CAR and had superior predictivity than D-dimer alone. Conclusion : DAR is a promising objective tool for aSAH outcome prediction. A high content DAR was associated with disease severity and unfavorable short-term outcomes.