Objective: Aggressive surgery seems mandatory for poor-grade middle cerebral artery (MCA) aneurysm with associated intracerebral hemorrhage (ICH). However, primary decompressive craniectomy (DC) is controversial. We performed a case control study to define the role of primary DC. Materials and methods: We analyzed data from the two cohorts: a multicenter prospective poor-grade aSAH registry study (AMPAS); and the National Clinical Research Center for Neurological Diseases (NCRC-ND) database of poor-grade patients. Outcome was assessed by modified Rankin Scale (mRS) and was dichotomized into favorable (mRS 0-3) and unfavorable outcome (mRS 4-6). We compared major complication rates, mortality and outcomes between primary DC and control groups. Results: Twenty-four patients with primary DC were included in the study group. Fourteen patients without DC were included in the control group. Patients with younger age and lower Glasgow coma score (GCS) more often underwent primary DC. Major complications did not differ between the two groups. Fourteen (58%) patients had a favorable outcome, and the mortality was 29%. Primary DC appeared to have lower in-hospital mortality and have better outcome. Adjusting for age and admission GCS, primary DC was not significantly associated with decreased mortality and improved outcomes. Conclusions: Although primary DC does not increase postoperative complication and mortality risk, current results showed primary DC does not seem to be significantly associated with improved outcomes. However, more than one half of patients most benefit from primary DC. Further prospective controlled studies are warranted to clarify the issue. (C) 2015 Elsevier B.V. All rights reserved.