Background: Simvastatinmight be beneficial to the patientswith aneurysmal subarachnoid hemorrhage. However, the results remained controversial. We conducted a systematic review and meta-analysis to explore the efficacy of simvastatin for aneurysmal subarachnoid hemorrhage. Methods: PubMed, EMbase, Web of science, EBSCO, and Cochrane library databaseswere systematically searched. Randomized controlled trials (RCTs) assessing the effect of simvastatin versus placebo on aneurysmal subarachnoid hemorrhagewere included. Two investigators independently searched articles, extracted data, and assessed the quality of included studies. The primary outcomes were delayed ischaemic deficit and delayed cerebral infarction. Meta-analysis was performed using the random-effect model. Results: Six RCTs involving 1053 patients were included in the meta-analysis. Overall, compared with control intervention, simvastatin intervention had no influence on delayed ischaemic deficit (RR= 0.99; 95% CI= 0.78 to 1.27; P = 0.96), delayed cerebral infarction (RR= 1.17; 95% CI= 0.60 to 2.29; P= 0.65), mRS = 2 (RR= 0.97; 95% CI = 0.87 to 1.09; P= 0.61), vasospasm (RR= 0.79; 95% CI= 0.49 to 1.29; P= 0.35), ICU stay (Std. mean difference= 0.04; 95% CI=-0.54 to 0.63; P= 0.88), hospital stay (Std. mean difference= 0.01; 95% CI=-0.13 to 0.14; P= 0.90) and mortality (RR = 0.71; 95% CI= 0.25 to 2.05; P = 0.53) after aneurysmal subarachnoid hemorrhage. Conclusions: Compared to control intervention, simvastatin interventionwas found to have no influence on delayed ischaemic deficit, delayed cerebral infarction, mRS = 2, vasospasm, ICU stay, hospital stay, and mortality in patients with acute aneurysmal subarachnoid hemorrhage. (C) 2017 Elsevier Inc. All rights reserved.