Hydroxymethylglutaryl coenzyme A reductase inhibitors (statins), which exhibit beneficial cerebrovascular effects by modulating inflammation and nitric oxide production, have not been evaluated in acute aneurysmal subarachnoid hemorrhage (SAH) patients. The effect of prior statin use on 14-day functional outcome and on prevention of vasospasm-induced delayed cerebral ischemia (DCI) or stroke during hospitalization was analyzed. We conducted a 1:2 matched (age, admission Hunt and Hess grade, vascular disease/risk history) cohort study of 20 SAH patients on statins and 40 SAH controls. The primary outcome was functional outcome at 14 days (Modified Lawton Physical Self-Maintenance Scale and Barthel Index scale scores). Secondary outcomes were 14-day mortality, Modified Rankin Scale score, DCI, DCI supported by angiography/transcranial Doppler TCD, cerebral infarctions of any type, and TCD highest mean velocity elevation. Statin users demonstrated a significant protective effect on 14-day Barthel Index scale and Modified Lawton Physical Self-Maintenance Scale scores (77 +/- 10 versus 39 +/- 8, P = 0.003; 12 +/- 7 versus 19 +/- 9, P = 0.03, respectively). Moreover, statin users demonstrated a significantly lower incidence of DCI and DCI supported by angiography/TCD (10% versus 43%, P = 0.02; 5% versus 35%, P = 0.01, respectively), cerebral infarctions of any type (25% versus 63%, P = 0.01), and baseline-to-final TCD highest mean velocity change of 50 cm/s or greater (18% versus 51%, P = 0.03). SAH statin users demonstrated significant improvement in 14-day functional outcome, a significantly lower incidence of DCI and cerebral infarctions of any type, as well as prevention of TCD highest mean velocity elevation. However, we did not find a significant statin impact on mortality or global outcome (Modified Rankin Scale) in this small sample. This study provides clinical evidence for the potential therapeutic benefit of statins after acute SAH.